It's smart to save those receipts
Stores will likely keep a record of your payment history, but you should also have your own records as a backup, says Nadine Samter, attorney with the Federal Trade Commission.
"You want to keep a record of your payments, independent of the company, so that you can establish that you've made all the payments," she says. "You don't want to rely on the merchant's records."
Save each receipt you get when you make a payment. If you're making them online, store them in a dedicated file or print them. With brick-and-mortar receipts, throw them into a big envelope, box or cookie jar -- something you won't lose. If you tend to lose things, make copies and store a set off-site, for example, in a file at work.
Also consider using a payment method that allows you to track and date your payments -- like a check or credit card, says Sherry. Putting each layaway payment on a credit card allows you to track each payment. But remember to immediately pay it off, she warns. That way, you're not putting the entire debt on your card at once and just revolving it.
Using a credit card, Sherry says, obviously won't "work for everybody, but it will give you more dispute rights."