Bad service

I have been encountering issue with Nedbank these 3 few weeks regarding my account being frozen without warning.It was at the supermarket trying to make a purchase when my card was declined.You can imagine my embarrassment.I called the call center first and the account was checked.There was no problem with it.The agent then requested the account to be unfrozen.I was able to use the account for just a few days then it was frozen again.I went into the branch to check what the issue was and the tellers were confused because in the system there is nothing wrong with my account and it is FICA verified.They requested my account to be unfrozen again which was done and after a few days, the same story.I had to go in again and request for the account to be unfrozen again.After 2 days I had the same issue.Again I had to visit a branch.I was then advised to bring in my workcontract ,passport and workpermit which I did the same day.That was on Friday the 13th of December.According to the teller this issue would be solved the following Teusday.As I am typing now I just left the branch again and nothing has been solved.The department that is going over this has not even responded to the email the tellers sent.I would like to know if Nedbank maybe does not want foreign nationals banking with them anymore?If so,They should just say it.