Oil leak 1980 kz550

Hey I need some help! Im not a motorcycle tech at all... I have a 1980 KZ550. I just got this back from the shop, the mechanic said the advancer and contact points and plate needed to be replaced..? Thats what I has told..SOOO $400 later now it pushing oil up the filter on top of the motor (See Pic). I just checked the oil and it seems almost bone dry! Help me out guys I feel like I got took already from this guy and I hate to bring it back... What do yall think?

OK so I've determined thats the breather cover and the filter is covering its some kind of relief valve or something.. what would cause the oil to be pushed back up through that?

Mine was doing the same think but I had a hose running into the air box and hats where it all went. When was the last time you changed your oil?? I would like to know the answer to this as well. Once I changed my oil it wasn't coming out nearly as bad as it was when I got mine. but just a little bit. Maybe the oil got thinned out and that's what was causing it to blow through so freely??

Sounds like a good place to start thanks!

First make sure your oil level and oil condition is correct, as if overfilled it will blow out the breather.
Hopefully the guy working on your bike, has set the ignition timing correctly and checked not just the Initial but the Full Advance of the ignition timing. Excessive advance can cause the engine to be damaged, showing up as high crankcase pressure which comes at the breather.