not happy with the service at all

I bought a phone at Vodacom north park mall Pretoria north with 2000 talking points,and they gave me a 535 lumia. I was looking for 640 lumia and they did not have it in stock, only to find out that 535 phone was not working properly and i had to take it back the same day before even 9 hours and they never gave me a new phone they said they will take that phone for repairs. I was shocked because i know that there's a 7 day period to exchange a phone if you are not happy about it. So now i want my talking points back, that shop they're not helping me at all i have being driving there for the past three weeks now almost everyday i spent lot of money on these up and downs! And i do not have the time!