Selling phone that you guys now have glitch problems.

I was telephonically contact Oct/Nov to upgrade my contract. My telephone is an business phone so its critic that my new phones work 100%. So they suggest that I take Hisense infinity h40. I took out 2 accounts. Both phones experience glitches and I went to our local vodashop @ gardenroute mall where they informed me they discontinued hisense range end last yr since to many complaints with constant glitche problems. Went for an 2nd option at the Yorkstr vodacom same feedback. I had to take out a new contract for an new phone since my 2 month old phone not working anymore. So now I have to pay extra account , this is very upset. I hope someone will contact me to explain how you can do this to an 20yr long customer.