If you're waiting for call sre jobs, of course you have to answer the phone so you need to have a prepared speech to recite to him when he calls again - note when as you can put money on him not having given up yet.
Next time he tries it on cut him short and assertively (ie. calmly and slowly in a clear, firm, voice) say 'I am telling you this once, and once only, and I want you to understand that I mean every word I am about to say. Hell will freeze over before you get another penny out of me and should you find a solicitor dumb enough to contradict what I've been told, I will fight you tooth and nail in Court. This is all I have to say to you and if you call me again or attempt to make contact with me in any other way, I will report you to the police for harassment'. After you've said your piece, hang up the phone.
PLEASE NOTE: do not put the above in writing or text - it is to be said once only and, should there be occasion thereafter, it is to be referred to as 'I've said my piece and my position has not altered'. Followed by 'now fuck off' if you feel so inclined.
Given the nature of the man, this won't necessarily stop him from continuing to make demands on you and, of course, he's got the ow to play nasty cop to what will be his next role as nice cop as he's resorts to 'I never wanted to hurt you, I only want what's fair, let's be friends' and other such shite to convince you to part with what is legally, solely, and rightfully, yours and yours alone.
Know that you're strong, confident, and capable, and on the basis that we're all related, channel Elizabeth as the Spanish Armada headed towards these shores: 'I know I have but the body of a weak and feeble woman but I have the heart of a King, and a King of England, too'. Feel that energy empower you as you see this fucker off once and for all.
Or channel Catherine Tate's 'Am I bovvered' 