Obviously rules are different here in Canada, but there was a similar situation here (not involving me). There is an lco called Grass Roots Lawn Care. Another guy (arborist and lco) started a company called Grass Roots and Tree Trunks. The original Grass Roots guy tried to make him change it, but because he had never registered his trade name with the province there was nothing he could do about it. If you can I'd make sure he changes his name, or change your own.