Repair my phone and get it back to me asap or give me back my money, you have inconvienienced me for far too long!!!!

Took my four month old cellphone in for repairs because it just went blank, cashier said it would take about 3 to 4 weeks to get fixed but here I am without a phone 5 weeks later. The best thing your cashiers could tell me is that samsung still hasn't sent the phone back.Your customer service is pathetic