suggest asking them if they have notes (many companies will have this) in their files where the issue was discussed back in 2017. BEFORE you tell them why you are calling, ask them to read the notes to you.... if they say the agent told you not to worry about the blank, you have a stronger case to complain. if there is no mention of that (or states you are obtain the ITIN before filing) you are out of luck.
the way I read the guarantee, it doesn't cover bad information from the agent.
