lack of service and bad attitude

I bought a Lenovo tablet for my son last christmas after 2 - weeks it wasn't turning on i returned it to the store after waiting around and filling out forms etc they booked it and sent it back to Lenovo. After many attempts finally i got it back 4- weeks later repaired they said it was faulty. AGAIN 2 - WEEKS AGO THE SAME THING IS NOW HAPPENING! I have returned it to the store and they say it has to back for checks i do not want it back and surgested credit me and i will pay the difference and buy an ipad as my son needs a tablet for school. i do not think its fair now that i have paid for something and 6 - weeks its been at the supplier alltogether. The staff have a carefree attitude are not helpfull in the slightest and think that they are doing you a favour.