Agreed Cumulonimbus. It happens all too often and legal loopholes mean that it will continue to happen, and suppliers such as yourself will continue to suffer.
That said - don't know an easy way around it, since those involved can reinvent themselves under different guises literally and therefore cannot be legally prohibited from entering the business once again.
Also, strong (yet failed?????) brand names do make sense to be re-used when the public holds a particular affection or confidence for that brand.