WHAT SHOULD I DO ??

Long story short, my ex and I want to fix up our relationship and try to make it work again but he’s so damn difficult to get through . I’m trying to help him and guide him through out steps how we can try to fix this but he’s just impossible! He wants to solve things/ do things the easy way meaning to work less and put less effort to make our relationship work but I’ve told him it’s not that easy especially in our situation. Every time I try to communicate with him , he gets mad easily, tries to shut me up or even change the conversation, then usually ends up yelling at me and hanging up the phone then calling back . I don’t know what else to do! I don’t know how can I get through him he’s like a damn brick wall. An option that I started thinking about is putting an ultimatum. Either he stops & starts taking action or I’m giving up and leaving . What do you think ?? If you want more details , I’m more then happy to share ! Please help I would very much appreciate it!