They stopped my services

I have been a customer of Barclays Bank for an year now and they have stopped my card without any notice or warning. Not only the card, but online banking as well, they have refused to give me my money. I have done nothing wrong, my payments were always on time yet they have stopped my services and upon contacting the customer service, they say that I can’t utilise my account for 15 days. One of the worst banks, I would suggest if you have any money with them remove it and invest somewhere else.