Horrible service

There is a hold on my revolving account. Apparently there is money outstading, but my payments go off via debit order. So I can not understand why is there a hold on my account. I have contacted fnb numerous times and no one can help me. I do not know what is happening with fnb, but my husband also has a lot of problems with his account. He switched to standard bank. Maby I must switch as well. The service is really horrible.