Bad Servive

At the beginning of October 2015 I changed my banking details with Vodacom which they confirmed via email. On the 7/11/2015 I get a snotty sms stating my account has not been paid. Went to the Menlyn branch on the 9/11/2015 where I was informed that I owed them 1 month because they did not present the debit order, paid them the outstanding amount and was told I was up to date only to find out the next day the 10/11/2015 that they presented a debit order for two months subscription How does this work Vodacom, over the last two days you have collected R2781.81 when it only should have been R927.27. If it was not for the contract I would have left you for another service provider even though I have been a loyal customer with you for many years.