Wedding dj left early

We hired a DJ for my daughter's wedding and signed a contract for 3 to 7 pm. When we booked i told the DJ it was a small reception but still wanted a fun atmosphere so we hired him.
Many guests actually felt it was very boring and he didn't play anything really upbeat and fast. Everything was super slow songs. Anyways so no one was really interested and people started leaving early. I let the DJ know I was going up to clean up ceremony area and id be back. When I came back he was gone. My parents and other family didn't say anything because they didn't think it was their place to do so and he didn't ask anything about packing up and leaving early. So we paid for 4 hrs of music and we got 2.5 hours instead. Is this something I should be partially refunded for? How do I go about addressing this???