EXCLUSIVE

A rep for Scheana tells TMZ the star has never received any complaints from neighbors or management about weed ... as for the cat, we're told Scheana's cat isn't allowed outside and the one in the lawsuit is another neighbors.

"Vanderpump Rules" star Scheana Shay's weed puffing parties are out of control, just like her black cat ... according to one pissed off neighbor.

Scheana lives in a fancy L.A. high rise apartment, and a guy who shares a wall with her says his unit's been inundated by marijuana clouds drifting from her crib. He ain't happy about the contact high.

According to his lawsuit ... his spouse and young kids are getting nauseous from the smoke, and he's fed up with the noise that goes down when Scheana turns up. He even calls out Scheana's black cat.

He says she leaves it outdoors with its food ... which attracts ants that constantly scout his kitchen, bedroom, closet and bathrooms for more grub.