Re: Copyright Infringment
If you indeed have copyrights (rather than trademarks), they would be for the software itself, not its trade name. Trade names can be trademarked if they are sufficiently distinctive and not merely strings of everyday words. I think "Easycab" probably could be trademarked in the combinations you give, but it is by no means a certainty. However, you are not making a clear distinction between the protection afforded by a copyright versus that afforded by a trademark. There is some overlap, but not much.
As to whether "Easy Cabinet Design Software" infringes "Easycab," I'd say you have an uphill battle establishing a case; first, because the phrase "Easy Cabinet Design Software" isn't itself trademarkable, because it is a string of ordinary words and lack the necessary distinctiveness, and thus it's use wouldn't offend a trademark; and secondarily, because the phrases may not be sufficiently similar to create a high risk of consumer confusion.
This is kind of an offhand opinion, and I'm hopeful that another LawGuru attorney who practices in this area on an everyday basis will weigh in with another opinion. Otherwise, I'd say that since this possible infringement is causing you actual losses, it would be well worth your while to have a consultation, in person, with a trademark attorney in your locale.
I would like to suggest two other possibilities. First, the other firm's software may be infringing your copyrights......have you had your software engineers and code designers look at the competitor's product to see if shows signs of being "borrowed" from your product?
The other possibility is that the competitor may be diverting Web traffic from your site by another kind of forbidden unfair business practice known as "cyberpiracy." Generally, this illegal practice consists of running a Web site that diverts business from another established firm by lulling Web surfers into thinking they're dealing with the better-known firm. You can find typical examples, references to the U. S. Code, and a better definition of what is illegal cyberpiracy on line by entering that term in a search engine.
Sorry to be somewhat negative about the chances for restraining this competitor on trademark grounds alone, and another lawyer may disagree with me, but I think the copy-cat is probably not doing actionable infringement.