Un fair charges

I had an arrangement on 7may 2020 regarding my account with Lydia oratile maje concerning my Altech nelster account to pay amount of R414.90 on the 7 May then the payment was made on the same day and the prove of payment was sent to them,what is annoying now am getting calls from them every day that my account is not updated I must pay R195.00 this month while my monthly installment is R124;00 for the device where does the R71,00 comes from that’s make my account to be R195,00 cause I payed what was required on the arrangement I need a clarification on that why the account is still with them and when you call their call centre asking that question from one of them her name is Ntombi she doesn’t give any explanation she said it your choice to pay or not what type of an answer is that while am trying to get explanation can you guyz please try and resolve this issue