Over charging of account

Good day

I would like to file a complaint.

For the past couple months I have been going back and forth with TFG's Customer service via email. (Proof of this correspondence is available on request) regarding over charges on my account

TFG has been over charging my account for as long as they can. They have been charging me interest on insurance x 3 (Different packages), they have been charging me interest on an interest free 6 month plan (as per their T's and C's), they recently started charging me sms and email fees which is soooo expensive it blew my mind away. I questioned TFG about these charges and I'm still waiting on answers. I have requested that a team leader, supervisor or even a manager contact me back via telephone to explain to me but this too has gone down the drain. Every month I pay my account via eft no later then the 2nd or 3rd of each new month, and because of this im being charged interest because my due date is on the 1st of every month

As the consumer/client don't i get a grace period after due date to pay my account? On their statements that they issue every month it shows that they only charge interest when statements are released which is the 11th or 12th of each new month, this was also one of my questions that i asked.

Im hoping by using this platform i will maybe get an answer because TFG ignores me point blank and also im not an accountant but i would like to have answers if im paying for something that im not using

Regards