TERRIBLE SERVICE at samsung tygervalley in cape town

In april 2017 I took my phone to Samsung tygervalley for screen repair under warranty.it stayed there for over almost 3weeks and they kept on saying they are waiting for parts. During the third week I booked it out as I was travelling and not knowing when I will be back in cape .

A week i came back in town ,i gave them a call to ask if they have parts,and they said yes.so i immediately took my phone in,the technician helped me to fix the screen that day from 1pm and by 6pm my broken screen was fixed. within a month i figured that the back part is lifting 'meaning it was not closed properly.

last week of July realized that the issue of the back part lifting is getting worse, so i went to Samsung tygervalley again and the technician examined my phone and informed me that when they replaced my screen that was broken they didn't put in back cover and front cover properly this is why its lifting, and he was suspecting that its a battery , but from what he sees, the battery is not swollen. He asked me if i would want them to book it in, with the experience that I had during April I said no you rather call me when you receive parts then I will bring my phone inn.

On the 19th of august ,after a week waiting for a call from them and calling them with no response i was starting to see cracks on the screen. I immediately visited the store to ask if they have parts.The manager was there and he commented and said it only need a tape it will stick together .As i was still confused, i was told to come back on the 20th as the tape is not at the store at that moment. I went back on the 20th August,and this time a female technician opened my phone and told me that the battery is swollen hence the back part is lifting i have to book the phone in, out of warranty because the screen is cracked and it has been fixed before, but i refuse to sign in a form out of warranty . They called supervisor and explain the whole situation and she said it must be fixed under warranty because the battery that is swollen is the cause for cracking screen. Till date i haven't received my phone. please help