You need to move on. This guy does not want you. Simple as that. **** happens. If you persure this you will look like a sore loser. Don't be surprised if the word gets out to avoid your company because you sue if you don't win the bid. You got everything to lose and nothing to gain. If this bid was going to make or break your business I would say you got too many eggs in one basket.
You have gotten some great advise from us now use it.
Only one person wins a lawsuit "your lawyer".
Making it the old fashion way.