Misled By Netstar

I have an issue, I was misled by Netstar. I had a 3 year contract with them and everything was paid for to cover the three years. Three months before the expiry of the contract I was called and begged to extend my contract with them of which I agreed after I was told that I was going to start paying for the new contract monthly after the expiry of the old contract. To my surprise they did not wait for the three end of my old contract they started deducting money that same month something that I had not agreed to otherwise I would have let the old contract finish before I would renew. I have asked them to look at this they have been dilly dallying. Netstar please resolve this! Thank you