FNB Complete Fail

I went to FNB Seapoint to apply for the Conexis X1. I received the mobile device on the 26th March from the branch. The following day when I actually started to install whatsapp and other applications the phone just started to reboot itself and went back to home screen. Then the Saturday evening 31 March I tried to make contact with FNB technical department as my phone started doing the same thing but this time it reboot the entire time for like 2min then was told that they dont operate weekends and public holiday. I decided after making contact again to the FNB technical department to take the phone back to the Seapoint branch. What really made me very upset was that they told me I am out of my 7 days which does not make sense as I have tried to contact FNB technical department which does not operate weekends and the branch I purchased the device by is also closed on Sundays and Public holidays. I have spoken to the Branch Manager Raul Draai and he advised that the phone must go back for repairs/ replaced as he cannot replace it at the branch. I cannot be without a phone for a month due to a faulty handset supp**** by FNB!! This is really pathetic service as I was within my 7 days but how do I log it if the technical department and Branch dont operate public holidays and weekends.