Nexus 6 crackling when making calls using voLTE on T-Mobile.

I have this annoying issue where if I enable voLTE on the Nexus 6 the call quality is horrible. It crackles really bad and I can barely understand the person but when I talk they can hear me no problems. It even crackles when I call someone and it is ringing for them to pick up. If I turn off voLTE and use HSPA for the voice calls they are so clear with no crackling. I called T-Mobile dozens of times and first they said that they were upgrading and provisioning towers but today with voLTE off I got a missed call as I was next to my phone and it did not ring except the sound it made saying new voice mail. Not the first time as I got a missed called last week with voLTE off. I am running out of ideas and I am getting tired of this phone. The last problem I had was major WiFi slowdown streaming music it would start to buffer and my 60mbps connection speed would slow down to 0.1mbps on the Nexus 6 using a Asus router. Finally had to buy a new Netgear router to fix this.

Really need some kind of answer. Googling is useless actually giving me junk links saying that calls sound better on voLTE yea right. Really the only thing I found on here remotely related was the cracking speakers. I am at a lost and I might just end up getting a different phone and cut my big lost buying this thing. Also I am running stock rom using the newest build that Google pushed which did nothing in fixing Wifi problems with my old router and crackling calls on voLTE. Basically a worthless update.