I can't get past the part when you have to hack the missle so they don't blow up the founders tower

1. Play an operative.
2. Spend most of the time securing the area.
3. When your AI allies FINALLY catch up to you, start hacking the missile.
4. Move around the missile to avoid fire from enemies. You MUST stay by the missile to have the best connection possible. It goes so slow otherwise.

That's what I've done and it works every time.

Use the shotgun, kill and enemeys nearby then make sure that there is medic near you and have a few people covering you, then hide behind the console and hope for the best

When i did it, me and 2 friends kept the enemy at the hallways coming out of their base while a bot hacked it. Simply because the bots can do objectives but can't cover your back. Have 2 medics and 1 engineer with a turret and damage boost and you'll be fine.

I ran an engineer with assualt primary, smg secondary. Planted a turret on 1 side and sat behind it droppin tangos as they came in. Short burst is VERY important in this game. After about 5 rounds the recoil gets very unreallistic (I've shot full auto rifles). Just 3-5 round bursts at med to long range will handle it. Also aim center mass to drop em faster, leg hits are useless. Even with the tarded AI soldiers would drop me ammo if I got low enough.

But I don't have anyone to play with because I'm on ps3

I tried multiple times. It's a really hard mission. Basically I went in as an op. Secured area. planted device. Anytime an enemy came up I whipped out my smg and blasted him. At about 40% the bots finally came in. You could try putting down to easy if you havent already.