Credit not what expected to be

I am a customer at MRP and have been enjoying my shopping there but recently I have had bad experiences. I always used to buy airtime on my account and stopped that because I have discovered that there are always problems with my credit when I make in-store purchases. Now I know that when I bought airtime that it will be deducted from my credit but my credit will always be way less than expected. This is verrrrrry disappointing, BECAUSE I DO NOT buy airtime on my account for 2 months now if not more but still, credit is not what it should be and I HAVE NEVER been late on my payments and ALWAYS make full payments.

Now my installment has been R500 but I have been getting credit of R300. HOW IS THIS POSSIBLE. MY STATEMENT OF THIS MONTH HAVE JUST ARRIVED AND I added up the numbers and do not get to the same amount.

R 4,878.64 2018-01-31 PAYMENT R-500.00 2018-02-07 INTEREST 20.75% R 76.40 2018-02-07 CARD SERVICE FEE R 8.50 2018-02-07 CUSTOMER PROTECTION PLAN OPT 1 R 10.50 2018-02-07 LOST CARD PROTECTION R 6.00 CLOSING STATEMENT BALANCE R 4,480.04 CREDIT AVAILABLE R 300.00

4 878.64 - 4480.04 = 398.60 and not 300

500 - 76.40 - 8.50 -10.50 ====These are the deductions that came from the R500 that was paid but by my available credit it shows R300. My only conclusion is that i am being ****** each month of my credit and this is an INDICATION OF *****. I AM A victim of *****. -6.00 = 398.60 Please get back to me on the matter or I will be forced to take matters further. Regards

I send this email to customers service this morning before 9am and still have NOT received a response.