I play a multiplayer game with my friend and I have researched few techs, but if I want to use them the game say "Missing technology" but if I look at lab its say tech is researched .

So I cant use tanks or harvest antimater because of "Missing technology" but I cant research it because it say its researched. 

after 6 hours of gameplay we stop at dead end 

Hello,

Are you sure you did not get desyncronized? 

That could maybe explain why it seems the techs are unlocked but aren't functional otherwise.

If that's the case, please take a look at this to properly report a desync.

That would help a lot, thank you very much :)