Paying for fonechoice 's incompetence

I took out a phone from fonechoice in December last year. The device was faulty so I returned it. I got the device back in January after a long disagreement. To my surprise, the device was returned to me in the same condition, so again I called them up to inform them. The device was collected again, and after following up daily they finally returned it to me in March 2018. And again the device was not fixed. Again I had to get it returned. As usual I had to call them continuelly to check on them. By this time I got very irritated and stopped payment. Only then did they quickly contact me , and that to ask for payment. When I told them why I'm not paying they promised to get it sorted. Again the device was returned to me on July the 9th still in the same condition. However I continued payment. Again I had to return the phone on July 10th. Today August 20, I'm still waiting. I received no calls from fonechoice, no update, nothing. I was the one calling and fighting for paying for a phone I do not have, and eventually out if complete frustration I had my last payment reversed and stopped debit order. That again was the fastest way they contacted me, and not to help me, but to ask for payment. Till today all I get from them is empty promises and calls for payment and the interest I will pay for all the calls they make to me.