Why iPhone 5S and Beeline do not catch the network well?

Question

Beeline

I recently switched to Beeline and a classic problem began: the phone is still in place, it is online, but they can’t get through to me from time to time, I receive an SMS that they called me. Now I managed to catch myself what it looks like: I dial from another phone to my mobile, there is complete silence in the receiver. 5 seconds pass, an SMS arrives on my mobile that they called me. There is still silence in the receiver, and after 10 seconds, dialing to the mobile passes. But usually, no one seems to be waiting.
This usually happens in the same place, in the office. But sometimes it happens to others too. Most likely, it's not the device itself, because. With the previous operator everything was ok.
How can such behavior be explained?

Answer 1

Apparently, this problem is somehow related to LTE. If you turn it off, then the calls go through normally. I found out after this topic: habrahabr.ru/company/beeline/blog/229093
Beeline contacted me, they understand.

Answer 2

Open the previous operator for the test, if everything is ok with him, then you have a hell of a beeline in the office.