I know that some of the regions are protected territories, if not all. You may not have a choice of which dealer to use. No matter though, because the most reputable people can blunder and you can't afford a blunder ton the part of your home that every other part depends. to make sure that your foundation of any type goes well:
Have the engineering double checked at least for reasonability.
Hire a consultant who can and will objectively monitor the installation to make sure the specification is realized. a very good builder will do this for you as part of the service, but unfortunately most will not unless they are specifically required to. You should be able to hire an expert consultant or project manager for two days (1 day if the foundation is not large) for approx. $1000.00
As for the second part of your question about what to do in your case, I cannot make an intelligent response. Your written explanation is not clear to me and if I thought it was clear, the chances are too great that I could mislead you because of an unknown miscommunication. My recommendation is for you to go with the dealer if you know them to be reputable and buy some insurance with a professional who has allegiance to you. Your mind and body will thank you.
Have a look at the superior walls home that I built.