Review Fee charged without disclosure

I got my business bank statement and was shocked to see it is double of what it usually is. On inspecting I saw that Standard bank is charging me R480 for a "Review Fee". I phoned the call center and they informed me that it is an annual review fee when one has an overdraft facility - which I do have. She told me it is to revise my credit status in order to see if i still qualify for the overdraft. She also says it happens yearly.

1. Now first off - it doesnt happen yearly, this only happened to me in 2015 as well. And was rectified and the amount put back in my account. 2. Lets say it happens yearly or every 3 years for that matter, - this is something which shouldve been disclosed to me upon signing up for this overdraft. I already pay a yearly overdraft fee which was disclosed. So they can't come and add these strange charges whenever they want to without warning me of it or disclosing it upfront. 3. I try to get hold of my business banker, but to no avail. No one picks up at the 2x numbers I have called and no reply to my emails.

Standard bank, can you please look into this for me, otherwise i will have to take it a step further in order to rectify this or move my business elsewhere. Kind Regards