You might ask for such a cancellation, known as a charge-back, to correct a double charge or other billing error. Or maybe that product you bought online never showed up or turned out to be a counterfeit. Maybe you never made a purchase in the first place.

Subscriptions are one of the fastest-growing charge-back categories, according to Ranjita Iyer, senior vice president, cyber and intelligence, at Mastercard. Consumers have so many of them, she says, that they may forget they signed up. Or they may have trouble canceling them.

Charge-backs, which are on the rise, can be tricky. Because an increasing number of consumers are filing fraudulent disputes, many merchants are trying to put the brakes on these cancellations. So it’s important to play by the rules, or you might get turned down.

What’s worse, even if you win, you could end up losing. Consumers who have successfully disputed charges have in some cases been banned by Uber and other merchants, according to the Elliott Report consumer advocacy site. Companies may limit charge-backs to one per customer and maintain “merchant deny lists” that are shared with other sellers, according to Signifyd, one of many firms that have popped up to assist companies in fighting charge-backs.

Here are six do’s and don’ts to help you win disputes and minimize hassles.

You may have just 60 days from the time you receive your credit card bill to dispute a charge. So keep close tabs on your statements and check carefully for suspicious transactions. Signing up for purchase alerts can help.

Unless it’s outright fraud, card issuers expect you to try to work with the seller first. Vendors have an incentive to resolve disputes by offering, say, a refund, exchange or repair, since charge-backs can be expensive. Dealing directly with merchants is often the quickest way to get satisfaction and can help you avoid trouble later on. Merchants who lose charge-back disputes may file lawsuits or use collection agencies to recover funds, according to the Elliott Report.

It might take up to 90 days or two billing cycles to get the problem resolved. In the meantime, you have the right to withhold payment of the disputed amount, according to the Federal Trade Commission.

If you don’t recognize a charge, take the time to review the details. Check your calendar to see where you were that day, call the toll-free number that may be listed with the charge or do an internet search for the named merchant. (That’s how my editor learned that a baffling charge from “TWPSUB” was his washingtonpost.com subscription.) When you dispute a charge that turns out to be legitimate, it’s called “friendly fraud,” and too many false alarms could result in your credit card being terminated, says Mastercard’s Iyer.

Also call if the merchant is unresponsive. You can check your credit card’s website or app for details and to initiate the process. Visa, Mastercard and American Express advertise zero-liability policies that promise you won’t be responsible for charges you didn’t authorize.

Receipts, contracts, emails, invoices, online chat transcripts and other documentation can help you back up your claim and complete the charge-back process. Include backup documents in a letter to the card issuer. Also, read merchant contracts. I’ve personally been burned because of language buried in a travel agency document.