Double debit with penalty

Cell c I am appalled with this situation.

My debit order is on the 15th of the month but due to being in a different country at present my boyfriend pays the account cash before the due date of the debit order.

He paid the account on the 13th of December. From my statement I see it reflected on the 14th yet you still debited my account on the 15th and now you are charging me an extra R70 for late payment when in actual fact you received the payment. Are you expecting a double payment on an up to date account,with a penalty charge?

Cell c explain yourself. I have all my paperwork and evidence to prove you wanted a double payment. You have an option to rectify the current statement or we cancel our subscription.. I am not dealing with this nonsense again.