User Activity

On the last bill, there is a number that keeps forwarding their cell phone number to my cell number, each time I am charged 1-minute usage.  I have blocked the number but I do not know if that is enough to prevent further charges. 
I have been bouncing around for months now with mobility providers and Apple.  I have an iPhone X and it was initially configured to accept LTE connections but Apple has since changed it to only connect to 4G because my calls would drop.  It use to b...