Originally, someone was whining that a contract was given to the ‘lowest domestic bidder’. Aren’t tenders are all about picking a lowest bidder? And nobody is getting invited into tender, bidders are coming on their own.
As for preferences, government agencies in Russia obliged to pick either domestic or Belarussian, Ukrainian or Kazakhstani companies. If they are buying things, it must be made in one of the above nations. Picking from different countries is possible as an exception (for example if a quality of offered items or works is twice as good as domestic counterpart or if it’s a half price of domestic products). BTW, US or European companies are winning Russian tenders quite often. Surprisingly, these are Chinese companies which are the most discriminated there.
You’ll have to take it up with the person who made the original complaint, whether the bid was awarded due to corruption, or not.