Harrassment by your childs father?

My sons has no interaction with his father. i have tried to pursue him to be in his life and he has no want to at all. in fact since i have been making him pay child support, he wants to sign over his rights so he does not have to pay for him. This is his third child he does not want. Him and his new wife has been harrasing me over facebook messages to try to scare me into letting him sign over his rights. Not threatening but not stopping after i have asked numerous times to stop. I have told him if this is the route he wanted to take, then he could take me to court. It got so bad to where i had to block him from facebook, so they began to text me until i threatened to call the cops and it still continued. Can he get arrested for this?