Kris Jenner Facelift Lawsuit -- The Neck Skin Defense

Kris Jenner says the cosmetics company she endorses has NO RIGHT to sue her for getting plastic surgery back in June ... because the procedure didn't affect her face ... it just tightened up some loose neck skin.

The company in question -- called B&P -- sued Jenner earlier this week, claiming she breached a contract to endorse a line of their anti-aging skin care products ... when the famous mother publicly admitted to getting a facelift.

By doing so, B&P alleges, Jenner violated her agreement not to harm the reputation of the company and the product she's endorsing -- an eye care line called "Beautiful Eyes in a Bag."

But sources close to the Kardashian Klan tell TMZ, Kris is adamant ... the lawsuit is BOGUS -- because Kris' facelift didn't affect her eyes in any way whatsoever ... JUST HER NECK.

Kris' alleged agreement with B&P went into effect in March 2011 and was to be effective until March 2012 -- but Kris admitted ... she got the facelift in June.

So we gotta ask ...