My son opened a bank account once that required both of us to sign cheques or withdrawls (his request). I left it to him to manage his bills and use the account wisely and simply co-signed. What was I thinking??!! I am NOT his banker.
One day he came to my office and I knew he wanted "his" money to use and I refused to go to the bank with him. He went into a rage that I have never seen before or since. He was out of control with rage and, quite frankly, I was afraid. I asked him to calm down and then told him that I would go to the bank and simply take my name off the account and requirement to sign and he was free to manage his own money, however badly, and that I would no longer handle anything that he could and should handle himself.
He withdrew the money, went on a 2 day drug bender and the money was gone. I let that be his problem, and just kept a safe distance while he continued down the path of addiction.
I learned that we cannot control them, their money, where they go and what they do. It's an illusion to think we can "help" them into sobriety. It was a hard lesson for me, but one more to carry with me on my own journey and one I didn't need to learn over and over again.
"We" cannot save them, we cannot manipulate (however well-intentioned) and the more we try, the sicker WE get.
The hardest thing I ever did was to step back and let my son live his own life, make his own terrible mistakes and know that I could not rescue anyone who wasn't willing to rescue themselves.
That's a long answer to say "Yes, blocking his number is a wise decision, not to punish him but to protect yourself from the emotional damage that comes with trying to reason with an active addict".
I am cheering you on here, when our stories are no longer about "them" but instead about the good things we are doing for ourselves...we know that our own recovery is healthy and strong.
Hugs from my heart to yours.