short·change 
(shôrtchānj)
(shôrtchānj)tr.v. short·changed, short·chang·ing, short·chang·es
1. To give (someone) less change than is due in a transaction.
2. To treat unfairly or deceitfully; cheat: "a deceitful cook who skimps on ingredients and shortchanges guests" (Jacques Pepin).
shortchanger n.