Need recommendations for rent collection service or attorney in Detroit, MI

Does anyone know of or have recommendations for a collection agency or attorney that works in the Detroit, MI area that has dealt with collecting rents? I have called and researched many companies that seem never to send me information when request to use their services and guess don't care to work with me.

IhHave a rental and am attempting to collect around $7,000 from past renters. I know most collection agencies take a 50% cut. That would be better than nothing, but I can't even get anyone to respond.

Thus I'm asking if anyone knows about or had had a good company or attorney that they have worked with in the past to collect rents. Thanks in advance!