Poor service

I had a previous cellphone contract with telkom for my nova 5t. No problem ever and life was a breeze. Upgraded to the nova 8 and suddenly I have to get a new Sim card and after that it has only been problem after problem. Half of the apps I use are not compatible because of this whole Google thing, but when I upgraded nobody told me. Besides that my signal comes and goes every 5 mins, keeps going to emergency calls, I've been to telkom and I have already received two new Sim cards which according to them was the problem and then they app**** settings to my phone which also did nothing. So utterly disgusted in this service. My phone isn't even 3 weeks old and I'm so regretfully for taking it. Please contact me ASAP!