TIRED OF FNB - Please close my accounts

I am extremely tired and disapointed with fnb. I have been complaining about the same thing for the past 3/4 months. this is an ongoing issue. Every month i am unable to use my overdraft. even when i have funds in my account, the overdraft limit reduces. FNB is unable to resolve this. I have been with them for more than 15 years. I furthermore wanted a business account but with this i really cannot proceed being an fnb client. I not so long, lodged a complaint iro of a refund that they told me was due to me. i was simply sent an email, without any explanation, that the refund is infact not due to me. I am exhausted and i want this issue of the overdraft resolved today and i want to close all my accounts, including savings accounts. i am tired.