cellphone contract

i bought a phone on the 17th December. i started using on the 18th. it just switched on and off. i took it back to the store on the 21 December. they took the phone back however told me i will receive in 3 weeks time. how can i not get a new phone?why should it go for repairs?<br> <br> this is frustrating to me. t start off with. i am sure i didn't damage it. and i bought a phone as i need it. it defeats the purpose if i will have to wait that long. So i have not exceeded 5 working days. i want my money back for me to buy another phone. as i will only be back on the 25th of January in midrand. and cant wait for that long to get a phone. its unfair.