Can't make or receive calls

I’ve been to the store 5 times! Have tried wifi calling and just cellular calling. It’s been an absolute nightmare. I’ve been playing around in the settings for days and last night I turned off blue tooth and that solved my issue. I can make and receive calls. I have no idea why that made my phone work! In the mean time I contacted tech support and asked them for a 4G booster and it’s on the way. Tech support told me I didn’t need to upgrade to a 5 G because my network is only 4G where I live. I am very, very rural! Nothing is out here! I do want to thank you for replying on my issue.