Please can you help improve the phone signal on my iphone. I have been on ID-mobile for two months now, i have Aspergers and i live alone, so its very important i have a decent phone signal, so i can phone people when i need to. even when i am in the gym which is close to my town centre i can’t get a phone signal in the gym either (even though i’m connected to their wifi and have wifi calling enabled, i get i missed calls when i leave the gym) but other people on the three network (which IDM runs on) have four bars in the gym. PLEASE PLEASE PLEASE can someone help. Thank you.

Additionally, NO, i don’t live in a castle, so its not thick walls that are stopping the signal from getting to my phone and the internal walls in the house are thin and even with internal doors open it makes no difference. Is there a signal booster that can be sent to me? I know other networks do a boosters that work with a broadband connection and put the calls through the broadband, but i don’t have broadband (just my phone). Even when i stand near a window or door it doesn’t make that much of a difference. 
After looking into this on youtube i found out how you can find your signal quality on your phone and mine is bouncing between -116 and -136, which i have discovered is the poorest signal there is and i live in an urban area, so not like i live in the back of beyond. My postcode is BL7-9YL if that helps in resolving the problem.