CANT GET MY PHONE BACK

Late December I handed in my I phone 6 at Lichtenburg mtn for sending to mtn Repair Centre. On 35 February I received a email to pay R330 in their account so that my phone could be sent back to me after no repair was done because there was a function on at my phone and they are not allowed to work on my phone. Since then I visited the mentioned mtn shop almost 20 times only to hear that my phone is not there. Phoning them does not help because nobody answer their phones. I report this to the mtn customer-care via email who also not responded yet as their email read they will respond whihtin 5 working days. Once I was lucky when a person answered the phone at customer-care who gave me numbers to dail and do my own investigating . I ended up after several attempts at HVRC on the 8th may who confirm that my phone is still there after I send them a proof of payment that was made on the 5 of march. I visited the mentioned mtn shop on the 16 of may with no success again.I am paying for a phone for the last 5 months whom I did not have or cant get a satisfied explanation where it is.