failing to return my phone

I took my phone for repairs on the 24th September 2015,andon the 2nd October 2015 they wrote me an sms that says they are going to charge me R4200, on the screen repair, then I went to the shop on the following day to tell them that they must not repair it, coz I don't have money. and that they caused my phone to overheat when I took it for the 1st time. that's why it feel down coz it was too hot. but till today they don't want to bring it back, I always go to check it, they say its still far to came back, while its not even fixed, I wonder why I they keeping it? because when I took it for repairs for the 1st time, it took only 2weeks and my phone was back. now that I don't want to pay it takes 1month, for visiting Vodacom shop.<br> <br> <br> thank you in advance, hope u'll bring my phone back coz I need it.<br> <br> angry customer.