A college student and his girlfriend discovers windows to spy on their neighbors during Christmas only to find out one of them invades their home.

Based on your feedback, leaning towards:
"When spying on their next-door neighbor, a voyeuristic couple seeks revenge after discovering they burglarize their home"

Take care.

1) It's a fetish
2) It's one of their neighbors. They are envious.
3) They might obtain money to get their stuff back.
4) They retaliate by getting revenge.
5) They want to go after them.

Reading this, there are a few things I'd want clarifying.
Firstly, why are they spying? Boredom? Fetish? Are they looking for something specific?
Secondly, who invades their home? Why is it important that this person in particular is the invader?
Also, it is unclear how and/or the spying and the home invasion are connected?
Finally, what happens when their home is invaded? Do they retaliate? What is the person's plan when invading?
At this point, this logline reads as an idea for a story, rather than a story distilled to its essence.