Service and Billing is no strong point. USELESS

I added additional data onto my contract. I received my bill and was charged partial charges for this data but I only received it on the 1st of the month. After many phone calls and being transferred to useless people the amount was credited.<br> I received an sms to say it is reflecting on my account. When I go online to check, it is not reflecting. I call them and they say that I will be debited incorrectly and then credited the next month. I said its not acceptable. Why cant they fix the billing before my debit order goes off as it hasn't been loaded yet. Why must I wait a month to get my money back when its their mistake. Such stupid people and bad service. I have had so much trouble with them over the last two years. I cannot wait for my contract to end. I will never recommend them. They are useless.