Account blocked due to an invalid reason

I’m a reseller of preowned items, I’m an entrepreneur operating my business online, I’m less than 12 months using African bank, I decided to bank with African bank because I saw how it would be important for me to invest with it since it has reasonable interest rates while investing with them. My account has been blocked because of a client who failed to pay my balance after she has received her item. She owes me roughly 1700 as a balance after she made a deposit of 3000. I am really unhappy because my account has been blocked for 4 months now, I’ve been visiting the branch several times and I am to wait for the call, till today African bank has no communication with me. My money in stuck in the account and by now I would have been far with my investment if they didn’t close my account because I would have kept transferring money into my investment account.. banks should always phone or leave an email to inform us because there’s always two sides of the story. I’m falling back instead of moving forward wit my business.