Debit order date changed and now account in arrear

I called Toyota Financial Services on the 19th of December to change my debit order date, as my new Company will be paying my salary on the 20th of each month. I was advised to call back in 2-3 days as they cannot process it now as its too close to the new date. Which is understandable. I called later and according to the lady the new debit order date was set for the 20th of January (thus not the 1st as normally) and the contract period will be extended with 1 month and also one may only change debit order dated 3 times during the contract period. All seemed in order and I didn't think about it again. 2nd of January the premium gets deducted and I called the call centre again and asked what is goiing on? According to them the debit order date wan't done. I said the debit order will be returned as my salary will only be deposited the 20th. As such on the 6th of January the amendment was finally done. What I didn't know is that whoever changed it, only changed the debit order date and didn't extend the contract with one month as was initially advised. Now I get calls upon calls stating my account is in arrears. It's messing up my ITC record and I want it fixed ASAP. Nicoleen Keulder