Very Angry, Disgusted and disappointed

I went to mtn store @ Greenstone to book my phone for repairs on the 12 may 2015 the phone was booked & I was told it was gonna take 2 to 3 weeks for my phone to come back, the weeks later I went to the store to find out when my phone was coming back because it was now long overdue, I was told to wait one more week and that it would be back by then, I waited and still nothing, nobody bothered to call me, I had to call them again and this time I was told that mtn was on strike and that they are unable to tell me when it's gonna come back. ... few weeks later I received an s ms from mtn Quoting me 997.68 .....I do not understand what the quote is for because this phone is still under warranty and I've handed in all the receipts and nessesary documents to prove it..I even tried calling their technical centre and with not available... I received anther sis again and I then rejected it because I was now already so upset ...I went back to the store this morning to get my phone and theni was told that is not back yet and that I had to pay an amount of R300 for rejecting the quote I mean is this for real? !!. .I'm still getting charged after all this... Please help...SUPER ANGRY AND UNHAPP