Missing costumes

This weekend two people rented costumes from me and didn't bring them back. The telephone number that they gave me doesn't work (I just get a single beep and nothing else). The number that they phoned me from originally is also strange: Somebody occasionally answers but apparently cannot hear me. I tried from a cell phone and from a normal landline. After that, the line is never accessible, as if they are trying to ignore me.

As a result, all future people renting will have to fill out quite a long form before anything leaves my place.

The worst part is, that I will have to order those costumes again, which will cost me quite a bit, and I will have to wait one month at least. One of those costumes was very popular, the other one not much at all. The costumes were supposed to be back by 12 during the day. Somebody else was hoping for them to be back on time.