Stall Letter
If you've ever sent a dispute letter to a credit bureau and got back a response telling you to call them or go online instead, that's a stall letter. And it happens way more than it should.
The thing is, they can't actually force you to do that. You have a legal right to dispute by mail under the Fair Credit Reporting Act, and when they push back, most people don't know what to say next. So they either drop it or go through the online portal, which almost never gives you the outcome you need.