We definitely don't want to lose you, and we are happy to take a closer look into this for you. Please allow me to explain that indoor use is a real challenge for all carriers. There are many things that can block your signal when indoors. Here's a short but helpful video that explains more: http://spr.ly/6600HFzQr
In a case like this, where the trouble is indoors only, generally the relevant factor is going to be proximity to cell site. Due to physics, radio frequencies get reduced penetration through solid materials and thus indoor signal is hampered when compared to outdoor signal. This is the reason you may notice a difference when stepping outside. As no carrier can guarantee indoor coverage, we partner with our manufacturers to build indoor solutions such as WiFi Calling. Do you currently have a WiFi connection at home?