Can we continue to repair products that we do not represent any more, without the cause of legal action on us?

In my judgment, this question -- while asked very clearly by you, and obviously an important question on which you NEED legal advice -- is too complicated for you to be able to get a meaningful answer that you can rely upon based only on an anonymous consultation over the internet. (I say "anonymous," but you've already listed more identifying information than you ought to have. Your potential adversary may end up finding and reading what you've written if they merely have a "Google alert" or similar search-engine monitoring program set up to flag every new use of their company or product name anywhere on the 'net.) Certainly you run serious legal risks -- and the potential for being sued either by the manufacturer or some dissatisfied customer of your own -- if you in any way misrepresent your status to imply some endorsement from the manufacturer that you actually lack. That would potentially be a violation of at least one, and possibly more, of the "laundry list" provisions in the Texas Deceptive Trade Practices-Consumer Protection Act, meaning that a consumer could sue you not only for actual damages but for statutory additional damages in the factfinder's discretion (up to triple actual damages), mental anguish damages, attorneys' fees, and court costs. Although you say your customers are well-served and happy, the manufacturer may well take the opposite position, and they may have superior resources to yours, with which they can develop facts that would undercut or even overcome your factual position in court. They may claim that without their on-going authorization, training, and support, you can't do an "adequate" job of sales or service. If you were dealing with a commodity product -- selling doorknobs or printer paper -- it would be substantially harder for the manufacturer to prove that your presence in the market harms it. But the more unique their product, the more detailed the knowledge required to sell and service it, the more plausible their claim becomes. To give you a meaningful answer to your question, one on which you may rely with some confidence, you need to have a much more in-depth analysis of your situation than anyone is going to be able to provide you over the internet. A lawyer would need to examine all of the contracts and other communications between you and the manufacturer going back to the origins of your involvement with this product. He or she would need to look at your own course of dealings with this manufacturer; at your current and historic patterns of dealing with customers (i.e., the proof to back up your assertion that customers are happy, etc.); at whatever information may be available concerning how the manufacturer relates to other "authorized" sales and service representatives; and at any applicable trade laws, possibly including international treaties and commerce agreements. No lawyer is likely to be able to give you any useful advice off the top of his or her head; a lot of work will need to be done by the lawyer, with your company's full and close cooperation and involvement, before you will be able to get a confident assessment of your potential legal risks, rights, and remedies. And certainly when it comes time for you to communicate sensitive information to the lawyer, or for the lawyer to give you his or her resulting advice, that should take place under the cloak of attorney-client privilege -- not on an internet website. You're obviously already on the manufacturer's radar screens. You should take seriously their "termination letter" and its demands -- not because they are necessarily valid or because you definitely would lose, but because it represents an imminent and real threat to your investments and plans. If this part of your business is worth trying to save, in other words, you can't afford NOT to engage a qualified lawyer to do the hard work necessary to advise and, potentially, represent you on this problem.

Your question is one that cannot be answered without developing the facts further and reviewing any contracts you or your company signed with the manufacturer. The facts you recite suggest that further research on the following issues may be availing: (i) Has there been a violation of the Texas Free Enterprise and Antitrust Act of 1983 (V. T. C. A., Bus. & C. § 15.01, TX BUS & COM § 15.01) which declares every contract, combination, or conspiracy in restraint of trade or commerce unlawful? Tex. Bus. & Com. Code Ann. § 15.05 (West); (ii) did the order to stop doing any more work on the manufacturer's equipment constitute a tortious interference with contractual and/or business relationships between your firm and your firm's customers? I would strongly suggest that you see a lawyer about this situation.