Tyga -- I'm No Malibu Squatter ... I Got My OWN Mansion

Tyga INSISTS ... he's not some broke-ass squatter who's refusing to pay rent on a MaBlibu crib -- in fact, he claims he just bought a $6.5-million mansion 20 miles away.

      But a rep for Tyga tells Lady Detective the lawsuit is 100% B.S ...         insisting he gave the landlord the necessary 30 days notice before he left ... and everything should be square.

Lady Detective  broke the story ... a Malibu landlord named Gholamreza Rezai sued Tyga, claiming the rapper is screwing him on the $16,000-per-month rent ... but continues to live in the home. 

Tyga also claims he's definitely NOT living in the home ... because he's shacked up at a brand new 9,279-square-foot mansion he purchased in Calabasas.

The rep says the landlord is being unreasonable -- and wants to keep Tyga locked in the lease because he can't find anyone to cover the hefty rent in such a crappy economy.

As for Tyga's new crib (above) -- we're told it's ginormous ... boasting 7 bedrooms, 8 baths, a movie theater, pool spa, waterfall, tennis courts, gym -- the works.