I receive calls from 903.581.2546 several times a day, how can I block this number?

Umm.... get a call blocker of some sort?

Calls insistently, from Tyler, Tx.  One right after another, does not leave a message, can only assume it's a telemarketer calling a number that has been on the national do not call list for years

Same here, multiple calls a day, but no one actually talks. Line hangs up after 10 seconds. Tried to call back and it tells me I can't reach the number or something like that.