Screen repair turned into broken phone

I took my Samsung Galaxy S4 in for a screen repair, and a 2 days after, i got call saying that my phone will have to go n for advanced repair as my motherboard in my phone has broken. there was nothing wrong with my phone except for my screen that cracked, somehow their repair guy has broken the board in my phone and now i'm sitting without a phone for a while, due to their technician breaking my phone, this is unacceptable! 2 day repair became a month repair!<br> i'm VERY UPSET with their service as well, i had to phone to find out what was going on, they don't even have the decency to phone the client!<br> <br> Please HELP!