false information and misleading the customer

I bought mobicell herox tablet on 29 march 2015.I have been experiencing problems with the phone such a the battery loosing charging power while on charge. The battery burst of the phone which then broke the back cover. I decided to take the phone back to fashions express and they booked it in for repairs on 25 august 2015. They told me it will take 7 days and they will contact me. I had to phone after them the entire time not once did they contact me out od their own. A staff member named bradley contacted me 2.5 weeks later asking me to bring the box of my phone which I then handed to the manager mariam. She told me that they will contact me in 4 working days, which never happened. I always had to contact them,which shows how unprofessional they are. She also said that mobicell is probably going to replace me with a new tablet as they requested my box. On friday 25 September 2015, bradley contacts me to tell me the phone is ready for collection. I fetched my phone on sunday the 27 september 2015, and mariam told me that they have replaced me with a brand new phone. I was excited when I got home I opened the box and it was my same old phone in worse condition, they must replace it