Concerned

My contract with them was 12 months but now I already paid 13 months with another month left. They do not say to me anything about 10% cash back they said they will give me at the end of my term. I have already paid a lot of money but still I have to pay where as we are approaching festive. Only if they can explain why did I have to pay 14 months instead of 12 and tell me when am I going to get that 10% cash back, then I can say something different about them.