My ex husband moved out of state and now harasses me more now?

My ex husband move to Colorado from texas. we have a 2 year old together when he was living here he left me alone about how i was raising our son. Now that he have moved he text me everyday telling that i did this wrong or that wrong. He doesn't pay child support I support our son on my own. I don't feel that he is a fit parent either i really want full custody cause me boyfriend wants to adopt my son what would i have to have to get that done also