Phone number *** blocked for the 3rd time in the past 3 months

For the past 3 month Cell C keep on Blocking my phone number . Payments go off via Debit order so I Cannot understand how I can be in arrears each month since July 2019. Payments went off as follows July 2019 deduction when off on the 25th in the amount of R365.39 - a week later my line is blocked with the SMS that an amount of R730.78 will be deducted within 2 days or as how I required. August 2019 deduction in the same amount when off on the 25th -2 days later I received an SMS to state payment received account unblocked . 2 weeks later my line is blocked again with the same SMS send. Septermber 2019 again on the 25th the payment when off - again 2 days later the SMS to say thank you for your payment account unblocked. To my dismay guess what ... now 2 weeks later and again my line is blocked and I just received an SMS from the Collection department to state that I must pay the R365.39 within 2 days or an Internal collection will be done. The sad part is that I have requested from them to do a thorough investigation on the 10th of September 2019 no reply. On the 18th of September 2019 with no reply . I am with Cell C for quite a few years and never had this problem. Regard Amanda Swanepoel