handed over after debit order disappeared

I recently installed a device , and was told that it would be R 159 PER MONTH after the first and second debit order it changed to R 189. for some reason . This was not a serious issue as i was happy with the device . Recently i received a sms saying i must pay a certain amount as the account was in arrears and some payments was not received , I paid the amount to nudebt , after telling them some payments was debitted from the account . Once the account was paid i asked for proof as i was in the proses of purchasing a home and the bank declined due to unpaid debit orders from netstar with dates that was not confirmed with me . Nudebt could not give me proof as the account was in arrears again due to a debit order that was not done by netstar . who is to be blamed ? how do we correct or do you need your device back as you already affected my credit score .