Sounds like you are having regulator issues. Regulator failure is common. The regulator is what actually makes the glass go up and down. When the regulator failes, the window has no support and slides down the door. The usual repair it to replace the regulator. A mechanic, such as one from YourMechanic, can replace the regulator and get your window working properly again.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing