Unhappy customer.

I am really not happy with the service of pace car rentals/SA moto lease at all. First of all am still waiting for the license disc from them as this one has expired. Secondly they failed to debit on time for my rental premium, I had to phone in myself and pay payment via EFT myself. Now all of sudden they are telling me about a buffer that's needs to be added to my debit order mandate and this was not stipulated from the onset of my contract. They can take their car back as I feel they are now taking advantage of their clients, seeing that rent to own is for people that can not get vehicle financing via banks. Now they see us desperate because of this now they are coming with other ways of making money. When was this buffer going to introduced had I not updated my debit order mandate due to them failing to make their debit order on time last month. This buffer was never mentioned in my contract l, now the it's been a year since I took the car with them now they are coming with a buffer jargon which they created. What ****es me the most is that am still waiting for the car license disc and it's nearly the festive season now. The grace period has lapses already but they are quick to tell me about buffer.