You should have waited for the police to arrive and stated your case. A friend had a similar thing happen in a case of demanding rent from a ex room mate while I was with them. They threatened to call the police. I said go ahead. There was another witness present by myself so it wasn’t like they could claim falsely that my friend had done anything wrong. When the police arrived, I explained to them the situation and they told me my friend would not be able to demand the money then and there but asked to see the paperwork and once verified, explained to us the process for legally squeezing the money out of the room mate right in front of them. Needless to say, that shut the ex roomie up and they scraped together their share of rent within a week. Police will usually side with the law and they generally don’t like watching people get taken advantage of.