After 7 years of banking with African bank, they have horribly treated me in the last 3 months

After 7 years of banking with African bank, they have horribly treated me in the last 3 months. They suspended by credit card account, and not a single person, from multiple branches and their credit cards department could tell me the reason for the suspension. Even their own employees from branches were frustrated but eventually someone agreed to urwarm the account just for me to access the funds. They then froze it again. The issue is that their collections department is now harassing me, they call even at night, yet, it's African bank's fault to suspend an account I use as revolving credit account. Horrible experience with them and worse calling their call center is a nightmare on its own