For more common British English phrases and their (mis)translations, see https://expatsincebirth.com/2018/03/04/what-the-british-say-...

One reason I didn't go back and check was that I always turn this off. Of course, I'm fallible and may have made a mistake here, and so I'll give them the benefit of the doubt on that one. Either way, I encourage people to check.

The other reason is that they didn't send me any kind of email telling me they were going to charge me.

This is British English for "I'm sure".

That's not what OP claimed.