Phone booked in for repairs and now gone

On the 27th of February I booked my Samsung galaxy s4 (I9500) in for repairs at Moorreesburg Autopage, because I have insurance at them. My screen was broken. Its now been 3 Months and I didn't heard anything of my phone yet. I called them every 4th day to hear if my phone is done, but then they cant tell me where my phone is. I don't know what to do next. hope you can help my to find my phone, because I pay for a contract with a phone that I don't have! <br> My phone number on the contract is ***