Our organization recently launched a software product. Let's call it product NONAME.
A few weeks after launch, a legal representative of a "NONAME Inc". contacted our organization to say that our product NONAME was in violation of their client's registered trademark (R). Cease and Desist was demanded, as well as revenues and the product itself.
On our own investigation, we have found that another separate organization (Company XYZ) actually has held the non-registered trademark (TM) on the term "NONAME" 50+ years in all 50 states prior to the initial use of NONAME by NONAME Inc.
We removed and re-branded our product - however if Company XYZ has TM'd term NONAME for 50+ years in all 50 states, does NONAME Inc. have any claim for damages on us for the use of the term NONAME?
Intellectual Property Law Attorney
There's a Ford Motors, Ford Model Agency, Ford Drums, Ford Gum, Ford Yacht Club, Ford Fusion, Ford Meter Box --- etc., etc. All of these different uses by different companies of "Ford" are lawful. There are innumerable other examples of multiple companies lawfully using the same trademark to brand different products, services, and companies.
Whatever word or phrase NONAME is, it can lawfully be used by lots of folks to brand lots of different products or services [as a trademark] and to brand different companies [as a trade name].
Your decision to re-brand your product [which disrupted your existing consumer's expectations and associations with your product -- and which must have cost you quite a bit] w/o speaking to a trademark attorney first was not a wise move.
Contracts / Agreements Lawyer
To add to my colleagues response. It is also possible that NONAME Inc. was given a license by Company XYZ to use the trademark NONAME. If your product's re-branding is going well without the use of the mark NONAME, I would say stick with that and to seek the advice of a trademark attorney to register the new mark as your own.