Client complain

Good day my name is liyema mathayi my husband and I rent contract car of 6month at we buy cars in Cape town airport we pay 6000 deposit and they have us car and we continue to pay their monthly instalment now december the contract was suppose to end we went at the airport to ask now we need to continue with contract what must happen we were told its fine we must submit latest bank statement we did and they have us another car few days we were called to come to the office we went everything was sorted fine now last week we receive another call that he must bring the car back he was suppose to pay another deposit for this car so we told them that we don't have another money now that is why we went to their offices so yesterday they went to him at Eastern Cape to fetch the car just like that..their services is very bad and it's annoying. Please help us what to do