If you are renting, complain to your landlord. You are paying for the parking - he has to provide it. If he doesn't, then write explaining that you are not getting what was agreed, and that you will be deducting $xxx from future rent payments until the spot is restored to your use. If you own, then you need to contact the management. If you paid extra for a car parking spot, then explain that unless the spot is restored to you, you will sue them, for the loss of use of the spot. Also leave a note on the car explaining that this is private property and parking is not permitted. Don't use stickers, let the air out of the tires, cover the car in offensive substances - these are all property damage - do this and you could get prosecuted (yes, stickers which don't come off cleanly - e.g. paper that tears, etc. - have been classed as criminal damage). At any rate, it wouldn't look good if things get nasty between the various parties.