Pay Attention and Resolve the Issue or I will bank elsewhere

I complained on the 12th January about being charged interest on R30k that was meant to have been transferred to budget. My complaint took FNB over a month to reply to and when they did they did not answer the question or refund me the interest that they charged me erroneously. If this is not remedied in 10 working days I will leave FNB after 20 years of banking there. Not prepared to but up with shocking service Ref ***