Yes, and that's why the payment to the retailer should have been the one in dispute, not the loan payment to Affirm. This is how it always works when you finance through a third party... it works the same way for a car loan, a mortgage, a credit card, etc.
You got 2 contracts here, one to pay back a loan, an another with the merchant, and sadly, when you don't pay back a credit, it get on your credit report...
So the one to contact, is Affirm, just like the one to contact in case of issue with a payment you made, is your credit card provider, and not your bank.
Your money flows from you -> affirm -> merchant in a singular transaction that is actuated by several automatically scheduled payments at the appointed dates.
No transaction flowed between you -> merchant to charge back. Given that actually litigating a dispute in multiple states would be thousands of dollars your only actual options are let them keep all your money even if they are in effect defrauding you OR issue a chargeback to the party that collected your money and let THEM handle retrieving any money transferred from them to the merchant who ultimately didn't fulfill their duty.
You will note that due to the high cost of retrieving your money the merchant has absolutely no reason not to just keep your money and ignore your phone calls. They after all already have the money they were going to make off you. It cannot afford to not pick up the phone for Affirm because it intends to via its continuing relationship to continue making money.
Fundamentally every transaction you undertake is intermediated usually through a multitude of levels whoever actually takes your money be it affirm or walmart has no right to be paid if the goods aren't delivered and acquires in addition to your money the obligation of making the customer whole first and then seeking redress up the food chain.
This is only untrue when there are two distinct different not directly related transactions. Get a generic credit card and use it to buy a TV for example. It would make little sense for chase to expect to be paid $500,000 for a house it turned out the seller had no right to sell or $50,000 for a car that was never delivered due to mischance. In both cases even though you had agreed to borrow that money the transaction would be unwound and not merely by you. This unwinding in case of a failure by merchant to deliver product financed is an expected part of such an interaction in part because such transactions almost always concern a great deal of money.
A situation whereby a singular purchase actuated by a button click is treated as 2 distinct transactions with virtually no recourse for any sort of misbehavior violates decades of consumer expectations and the ground rules under which we all presently do business. It is surprising and harmful.