Change to account without my consent /request

FNB was a really good bank years ago. Which is why I switched to them. Their customer service were really above and beyond. I find myself super annoyed tonight, because I receive a notice that my credit limit has been adjusted without my consent or request. I am tired of establishments doing whatever they please. And then they expect me to sacrifice my time and airtime to try and resolve something that I never asked for. I can also not fix it on the app nor log complaint on the app. Do not do things without people's consent. I am seriously ticked off and considering changing banks.