FNB is becoming not trustworthy to bank with

This two weeks FNB frozen my account for no reason, on the 18th FNB froze my account then I went to the branch the next day which I was advised that the analyst will give me a call back then unblock my account Since then I have been trying to reach out to them but to no avail. FNB didn’t even mail me to say why my account was frozen but I have been sending mails to Brenda.mnisi which is the analyst that blocked my account but she would write back or call back