Billing issues and poor customer service

When I took the rain contract I was told that this is a month to month deal and NO CONTRACT. So I did not hesitate to take the deal. Everything was fine for a good couple of months until I decided to skip a month in December since I was going home where there is no coverage for their network. They tried to debit my account relentlessly for weeks in December to no avail and I was subsequently locked out of the service since beginning of that month. I did not pay for the service until mid January when i came back to Gauteng, but to my surprise when I wanted to reactivate the service I was told that I am owing for December to which I rep**** no because I did not use the service. The consultant with an American accent told me he will escalate the matter to billing department for resolution. I was advised to pay the full amount for January for deactivation around 15Jan, which I did because I was desperate for service. I’m baffled by the fact that they did not Pro-rate my fee since I reactivated mid-month, but when you join mid-month they pro rate your fees. I have been trying to call since morning but no answer just some lousy music. I was told that after investigation I will receive feedback since they were still going to verify whether I used the service in December or not but no one came back to me, I only see debit order attempts on my account for different amounts. They system still tells me I’m owing, but how can I owe for a service I did not receive and when you say this is not a contract, again why do you not pro rate when I pay later in the month? I can’t reach you on your line and I’m losing money. please resolve my issue urgently. I DO NOT OWE FOR DECEMBER CAUSE I DID NOT USE YOUR SERVICES. Please remove those arrears.