Laptop not working refused exchange

I boughtba laptop at pep cell mvusuludzo on the 25the of august and on the 2nd of September the laptop went blank its still new i didn't knownwhats wrong i contact led help desk they said i should return it in store for exchange for the new one. When i arrive to the store the supervisor said that cannot be done. Because 7 days has already passed it can only booked to be fixed. Which was not explained to me on day of purchase and the supervisor gave me contacts ofbarea manager. Still no assistant i bought the laptop for business use now im stuck i cant do anything i am told to wait 6 weeks which is too much for me because my business needs to operate even now the area manager said will get back to me. She still haven't called I'm disappointed i just want mynmoney back imbtiredbofbthebwholebuo and downs