Debit order

I have an issue with Telkom i have a contract with them which of they must debit in my Old Mutual account but every month they dont and i must stop what im doing to go and pay them.. It doesn't make sense to me because i wanted to pay for myself every month end but they didn't allow me they said they will debit themselves but they only did it 3 times... I must leave my new born baby to go pay them every 1st day of the month because they dont debit.. This is really bad customer service. They must just allow me to pay it for myself so that i know every month end i must go pay them. Soon I'll be going back to work and if they continue doing this it will be a problem because I'll be busy most of the time.