Am defeated by the ********** service

I don't even know where to start as this is like my 3rd complaint... This is the worst experience in my life, from getting enxiety and panic attacks at work due to their errors. I work at a call centre in the complaints department and wow, I have a case open 2 weeks they don't want to give me my money due to stupid investigations and no response to the 4 emails I sent to their complaints team. I really need to change banks, you have ruined me and if you carry on like this, you will lose a lot of customers.