Terrible repair service from Samsung

My Samsung Note 4 was sent in for a free screen repair. I was told it should take no longer than 10 - 14 working days. We have phoned numerous times and they keep saying it is still being repaired. It has now been over 5 weeks and all Samsung has to say is that the phone failed a quality test and has been sent back to the repairs department. i was told they would follow up and cal me and its been over n week since then and i have still not received a call? We have even called the head office to ask for assistance but had no luck? I am paying a contract for a phone which i don't even have? I can't afford to sit without a phone as it is used for business as well as private. so please can someone help as this is unacceptable!! Why is it taking so long?