This is among the worst of the facts that have emerged in the wake of the company’s announcement on Thursday that thieves may have stolen up to 143 million Social Security numbers, dates of birth, names and addresses from its credit files. Armed with that information, thieves, blackmailers and enemies can make a lot of mischief. A credit freeze can prevent thieves from using your information to open new accounts, since lenders want to see a credit report before doing business with you.

On Saturday, many readers sent me tales of outrage and woe. They could not believe that Equifax and the other credit reporting firms, Experian and TransUnion, charge fees to freeze the credit files that they had not asked the companies to set up in the first place. Besides, isn’t keeping that information safe their most important job?

Nevertheless, consumers persisted. But when they pulled up the websites of Equifax, Experian and TransUnion, they often found crashed sites (because everyone else was persisting, too) or requests from the companies to write in or call instead. (For a variety of reasons — some of them security-related — the bureaus sometimes refuse online requests for freezes. Just be glad you don’t have to make the request via registered mail as I did back in the old days.)

Candy Sagon, in Reston, Va., had a typical experience. Equifax’s system worked fine. “Including the $10 charge they don’t deserve,” she said. But Experian’s site to set up an online freeze didn’t work at first, then kicked her to the snail mail option because she didn’t put in the amount of her monthly mortgage payment correctly when the site attempted to identify her. Then, TransUnion’s phone system disconnected her four times.

Dan Harrison, a Los Angeles media executive who is also a lawyer, said he already had a credit freeze, one that he’d set up after a previous breach involving another company. When he heard about the Equifax breach, his immediate instinct was to contact Equifax to change his PINs. His logic was this: Why assume that those were safe, given the circumstances?