There are cell boosters available.
When we went to Alaska we borrowed one from our son, who lives in Edmonton, Alberta. I only had to use it twice in 3 months. The signal on the phone was pretty much zero and up and down to one bar. I plugged the amplifier into the cig lighter socket, put the antenna on the hood of the truck ( magnetic mount), and held the phone and antenna "pad" together and was able to make my calls.I think I had 2 solid bars for signal strength. I think first use was in Alaska and second was in the Yukon, so both in bad cell areas.
If my memory is right(hahaha) the brand was Wilson.
Maybe you have a friend who has one who will let you try one before paying the outrageous amount they want for them.