Probably yes, at least as a starting presumption, if the purchase was an international shipment and you were the importer/recipient. U.S. Customs and Border Protection says that when you buy goods from a foreign source, you become the importer and are responsible for duties, compliance, and related import costs. CBP also warns that courier shipments often generate additional broker fees and customs charges that buyers mistakenly think were covered by the seller.
That said, "liable" is not the same as "must simply pay whatever UPS asks." A $1,600 post-purchase bill is large enough that you should treat it as a claim to verify, not an amount to accept blindly. Your real answer depends on five facts:
CBP's internet-purchases guidance is unusually direct: when you buy from a foreign seller, "you become the importer," and the importer is responsible for import compliance and duty. The same page says buyers are often surprised because courier shipments can add broker fees and CBP duties on top of the purchase price, and that a purchase price including shipping/handling usually does not include duty or customs-clearance costs.
CBP's importer tips page adds another important point: even if a customs broker handles the entry, the importer of record remains ultimately responsible for the entry and for applicable duties, taxes, and fees. In other words, "UPS handled customs" does not usually shift liability away from the buyer if the buyer was the importer.
That is the strongest reason the default answer is yes: if this was a normal international purchase shipped to you, customs-related charges generally follow the importer/recipient, not Reverb as a marketplace.
A valid customs framework does not automatically make a specific $1,600 UPS invoice correct. There are several common paths to reduce or defeat the charge.
If the Reverb listing, messages, or invoice said shipping included import charges, or used language like "no additional fees," "DDP," or equivalent, that is strong evidence the seller, not you, agreed to absorb those charges. In that case the customs law may still allow UPS to seek payment from the importer first, but you may have a reimbursement claim against the seller and possibly a marketplace dispute angle.
CBP explains that import bills can include actual duty, merchandise processing fees, and broker-related charges. Their guidance also says importers may be billed for storage and other costs if cargo is not timely cleared, and CBP's importer tips page warns that import examinations can generate third-party handling costs. If UPS billed $1,600, part of that number may be carrier-side fees rather than tax owed to the government.
That matters because some add-on fees are more negotiable or challengeable than statutory duty.
Duty depends heavily on tariff classification, customs value, country of origin, and whether any exemption applies. CBP's internet-purchases page warns that inaccurate descriptions or values can lead to the wrong duty rate. If the seller declared the wrong item type, the wrong value, or the wrong origin, UPS may have calculated from bad inputs.
The legal default is that the importer is responsible, but the shipping contract can allocate who UPS was supposed to bill first. If the shipper selected sender-billed duties/taxes, UPS should explain why it is pursuing you. If you refused the shipment before customs release, or the package was returned, that can also change what charges remain properly collectible.
Even where customs charges are legally yours, you may still have a contract or platform claim if the seller materially misdescribed the shipping terms, item origin, or landed-cost expectations. Your dispute may be against the seller rather than against CBP or UPS.
Reverb is usually the marketplace layer, not the customs actor. So Reverb typically does not replace the buyer/seller allocation that comes from the listing, checkout terms, and shipping arrangement. The key Reverb questions are practical, not theoretical:
If the transaction was transparently international and silent on duties, the customs default usually hurts the buyer. If the seller represented the transaction as effectively domestic-cost or fully prepaid, your position gets stronger.
Use this rule of thumb:
Request all of the following in writing:
If UPS cannot provide a clean line-item explanation, do not assume the number is correct.
Save copies of:
This is what determines whether you have a reimbursement or misrepresentation claim against the seller.
If UPS calculated off the wrong value, a bundle value, insurance amount, or incorrect commodity description, the bill may be inflated.
Use this order:
If "UPS billed me $1600 after purchase on Reverb" means an imported instrument crossed a border and neither the seller nor Reverb promised prepaid duties, the most likely answer is: yes, you are presumptively liable, at least enough that UPS can demand payment from you.
If instead the seller made an all-in pricing promise, the customs declaration was wrong, or the $1,600 includes inflated non-duty carrier charges, then the better answer is: maybe not, or not for the full amount, and you should dispute it immediately with documentation.
Yes, usually, if you were the importer/recipient on an international Reverb purchase. But you should not pay a $1,600 UPS bill without first getting the customs paperwork and a line-item breakdown, because liability for import charges is common while the amount itself is still very contestable.