have on the string
have (someone) on the string
To keep someone awaiting a decision. They told me they would call last week! I wonder how long they plan to have me on the string.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
have someone on the string
Fig. to have someone waiting for a decision. Sally has John on the string. He has asked her to marry him, but she hasn't replied yet. Yes, it sounds like she has him on the string.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.