I broke up with my ex a month ago. He has 1 small thing of mine that has a lot of sentimental value (it was a Christmas present my late mother bought me), so I just want it back as soon as possible. He left a large rucksack-worth of things in my home, which collectively have a lot more monetary value than the thing I want back. Last month he promised to give it back in January. I asked him to make arrangements with friends to meet up this month in my city (I live in a major city), and we can exchange things on his way to and from seeing his friends. He agreed.

But during the month since the break-up, he hasn't told me when he is coming to my city, has said things like being busy (meaning he made himself busy after we broke up because he's not usually busy every weekend), not wanting to carry a bag with him when meeting up with friends.

So I am worried that he's purposefully taking his time to give it back to me. How long should I wait until I contact the police to help me get it back? I know it's only been a month since the break up, but I am asking in case at the end of this month he still hasn't given it back to me.