Someone filled my dumpster in middle of night

Came to work and our dumpster will full - overflowing in fact with boxes that were not ours. I look on the camera and see the guy pull up get out of his truck and unload about 15 large boxes. I looked on line and it says it is illegal for someone to fill up a business dumpster that is not theirs- illegal dumping with $500+ fine. I called the Travis County sherriff's dept and reported that someone did this-I have them on camera- filling my dumpster. Sherriff comes out says it is not illegal. And he left. How is that ok? Now I have a full dumpster and it doesn't get emptied until Saturday.