Daughters father is on drugs...

My daughters (3) father (28) and I split up over a year ago, of course we've had our ups and Downs. But regarding our daughter there is no mediation that has taken place, no court orders specifying times of contact etc. We have verbally arranged that he calls Monday, Wednesday and Friday between 6-6.30pm to talk to our daughter but often fails this, as he is busy or has one excuse or another. He sees her when he has no other plans with his friends etc. He sometimes misses payments regarding information child support and I let this slide as I understand sometimes money gets hard, but this continued for over a month and then in line with this, a few weeks ago we started to talk again and one night he called me up crying, it was late. I asked what was going on and he said that he was addicted to Herroin and was using it to cope with a lot of stress in his life. I obviously don't have this recorded as it was completely unexpected. Since then he has admitted that he smokes it and is able to get anything he needs within 15 minutes of making a call. This is extremely serious and I am fearful of his outbursts that has now been noticed and very obvious since he has told me this. He has threatened to come to my house and take our daughter if I don't answer his calls, even though I have stated he is welcome to message, email or Facebook message anything regarding our daughter and I will reply as soon as I can. He deems this completely unreasonable and again threatened to turn up to my house, as well as telling me he will call and have welfare checks on our daughter every day until I answer his calls. I am getting quite scared. I am wondering how I go about getting him to perform a drug test without any actual proof. I don't want to seem as if I'm being petty and just making stuff up ? His moods are extremely unpredictable and are really scaring me. Please help with any information you may know.