I am not getting 4G LTE service on Iphone 6

[CRAYONZ]

Hello..

I am not getting 4G LTE service in my i-phone 6.

I am in an area that does have 4G LTE service...when I am about 1/4 mile away from my home I do get 4G LTE...but in my house it goes away.

With this problem if I have Cellular > Cellular Data > Cellular data Options> Enable LTE Voice & Data ON....phone calls go straight to voicemail.

if I have Cellular > Cellular Data > Cellular data Options> Enable LTE Data ON...calls come in as ring as normal and don't go straight to voicemail.

I went to Apple and they reset my phone updated and all that.

The local Verizon stores don't know why this is happening.

My son has an I-phone 6s and it does get 4g LTE.

Any help would be appreciated.

Thanks

Vincent