cash back funds not received

I am a very dissatisfied customer from old mutual, my kindness towards them has simply ran out,I am so annoyed with the way old mutual conducts a matter ,my cash back funds was supposed to be paid into my bank account but the had a different bank account and after I have provided my new banking details they still fail to deliver on promised dates,what bothers me the most is when you have missed a premium the will call you as quick as possible but when u supposed to receive money the are always having issues paying you (your own money)