any experience with collecting default judgement money from tena

We had really bad experience with our rental house in TX Dallas area. The tenant did not pay us rent for several months so we filed a judgment against the tenant with Collin county count. The court awarded us about $5000. We went with a collection agency but after several months, they told us that they are not successful in collecting the money(tenant does not pay). They said that we may try other agency.

Then we received a flier from a company called recourse solution in TX. This looks like a single person company. This guy asks us to assign every rights to him and he goes for collecting money and he gets 50% of the money collected. He is not a lawyer. I am worried and not sure what consequence will be with this kind of agreement. Does anybody have experience with enforce judgment in TX? Any collection agency recommendation?

Thanks in advance!