Faulty samsung Z3 fold

I took out a contract with telkom mobile about a year ago samsung galaxy z fold 3. They sold a faulty device as I've had the phone at samsung x3 to be repaired. This device should never have left the production line. If this warranty expires I will have to pay for fixing it. They refuse to replace it and now this device has been discontinued and replaced with a z fold 4. Meanwhile you're expecting payment every month. The quickest way you listen is none payment