I have to pay for their mistake!

I pay my account on time every month. So in January I was shocked to receive communication that my account was due. After investigating, I found that my last 2 eft payments were not reflecting on my account. After phone calls and emails, bank statements and explanations, the 2 payments were posted to my account. But now, I also have a charge for a sms and interest on my account. I have emailed about it, I have called about it. And it is still not sorted. I am tired of TFG now! I paid my account on time. I will not be paying interest and communication fees! My reference for the sms charge is ***| CS-***. I never received a reference for the interest.