I'm lost for words now

I've been a loyal customer for Markham for i can't remember always paying my account 150% even when zero due i used to pay towards my account. in 2019 Feb i met with a horrible accident now I'm crippled and get a gov. grant but used to pay some of the amount due and I help from my children but as I all know covid wrecked every walk of life ... pay cuts & even loss of jobs... so it became hard ... so tfg & i agreed from a 12 month account to 18 month account... I've been paying on time even paying more than the amount due knowing next amount will be lower but that never happened until I queried sorted.... Jan account my wife went to pay and found out example balance R1000 paid R150 should state R 850 but slip showed balance R1065 how is that possible i never used to check my receipts... so now I checked receipts .. i only got 6 months back & 2 other receipts is same story so how much more I was ****** and never check ... I sent them an email but never respond so that is why I'm on hello peter ... please consumers dont be like me and scrutinise your statement & receipts. I've been getting ********** but never knew until my wife picked that up.... well done by her