Rotten service

I am appalled at the service i received from JG, i booked my tablet for repairs (device not charging) with Joseph and what a gentleman he is, he called me to come collect my phone i was glad, i went on the 7/8/2015 but unfortunately my phone was not able to recognize my sim cards (realized when i got home) so i went back to the store the following day then my phone was re booked, i called JG after the 12/08/2015 but the phone was not even going through, i went back on Monday 17/08/2015 irate, demanding that they give me back my phone as no one is saying anything about the phone, i cannot take my phone for repairs and called to collect it only to find out that a new problem has developed while the device is in the repairers hands, nevertheless, I was very upset at the run around that i am being made to do with trips i do not plan TO DO due to this explainable nonsense as to why my device cannot detect my sims, to put a cherry on top, this rude woman MILDRED tells me that i will not threaten anyone at the store that i am not getting my device (Which i paid cash in full) and there is nothing i can do about, i bought 5 devices from JG sent most 3 to Nigeria, i don't deserve this sh**