How to deal with tanks?

My friend plays astra militarum tanks for this army and I feel they are completely broken. They have high movement, wounds, toughness, tons of guns, a 2 up save, amazing orders, and tailor made stratagems that are prefect for just about any situation.

I feel that they are more broken than anything else in the game right now. They can take the center objectives with no trouble turn 1 and still blast everything off the board before it can get to them for the most part. Then they have more OC than some units that cost more than them.

This makes me just want to drop my units in a furnace and quit the game when I play against him. I play necrons so my void dragon is about the only thing useful against them and a 300 point unit is less useful than a 180 point unit in terms of overall effectiveness.