If you are being used then someone is taking advantage of you and benefiting from this dishonesty in some way. It may be a relative who takes advantage of your compassion to have you do things for them, or a friend who only hangs out with you because you pay for everything all the time. Being used is not acceptable, and if you find out that someone is using you then the situation needs to be addressed immediately.
People never see what they did wrong but they see what you wrote on Facebook.
There's nothing worse than being used, except for denying it and allowing it to continue.
The worst feeling in the world is knowing you've been used and lied to.
No matter how bad people treat you, never be a bad person to take revenge.