Looking for an idiom or a slang word/phrase for a formal reply with no intent to help [duplicate]
You might consider fob off, a phrasal verb defined by Collins in this way:
If someone fobs you off, they tell you something just to stop you asking questions. [disapproval]
Ex: I've asked her about it but she fobs me off.
Don't be fobbed off with excuses.
While this Phrase Dictionary defines it as:
To put off deceitfully; to attempt to satisfy with something of inferior quality or something less than one has been led to expect.
(at this link you will also find the origin of the phrase)