Recently, I have not been able to revive or make any calls for extended periods of time, rarely I am able to make calls but most of the day, I am unable to make calls or use my mobile data, I think it's something to do with this icon, I haven't done anything strange or installed anything malicious over the past few weeks so I'm unsure what could be causing it, I have attached 2 images, one for the symbol when it is working and one where it isn't. (The symbols are on the top left of my screen next to the WiFi symbol and the battery %)

I have already tried restarting my device, shutting down and forcing it on airplane mode for a while before allowing internet again but nothing has worked, any help would be appreciated