Unfairness of changing my account without consent!

On the 9th December 2020,an amount of more than R3000 popped into my account from Ametlife. I didn't know whats Amedlife linked to so i searched only to find lot of ****s reported on reviews. In fear i went to the bank same day after work to enquire. The lady who attended me teased me for reporting that instead of just using the money. She then went through my portfolio and told me Ametlife is linked to Metropolitan so i should call them.

Then to my surprise she handed me her tablet and said I should sign. I asked for what? She said she will send me email to go through the offer for credit card even if im not interested to have a look at it.

To my surprise my account in no days was changed from premier cheque account to Fusion account. I really have no idea to whats happening. I called FNB multiple times to resolve the matter up to date, No one care.

Should I continue with the bank that's forcing things and not serving the customers right?