Bad business practice

i bought a Renault Clio 3 through rent to own at Big Apple via Planet 42, drove the car from Cape Town to East London and on the way it started making a sound in the engine which makes it loose power. i called the dealership they wanted me to bring it back to Cape Town and i said i cant with that engine. i asked them to atleast replace the car and they refused.Planet 42 kept avoiding me until they fetched the car, all i wanted was for them to replace the car now they harrasing me with calls and sms that i owe them