phone repair

On 15 Dec 2015 i bought a tablet at Jet clohing store. Two weeks after my tablet was not working. I sent it for repairs at Jet on 15 Jan 2016 and was told it will take 4 to 6 weeks to be repaired and not longer than that. On 15 Feb 2016 i went to check if it was repaired yet or not and was told my tablet has not been sent yet for repairs it still in the shop. They showed it to me still wrapped as i left it lastmonth. I asked now how long will i wait to hear from u again only to be told i should wait another 6 weeks??? I was not happy to hear that and even now the lady who assisted me could not assure me when i can expect my tablet back. I even attempted to take it and repair it myself and felt this will not be fair as its still under warranty and i also have an insurance with the store. I only used this tablet for two weeks but delayed to returned it as i was out of town. The service in terms of repairs is very poor and it seems like am not the first to experience that. The sales person even confirmed to me that cellphones take longer period to be repaired and its their system there is nothing they can do. Now what should i do with this matter because i am becoming impatient.