Underquoting and how to deal with it?

Hi experts,

Sister is selling her home and asking for a price between $1.15m – $1.2m
Selling agent claimed to be confident and therefore got the listing few weeks back.
Same price range written in authority letter and signed. Statement of info (SOI)
stipulates same range between $1.1m – $1.2m. Don’t know why but she never thought might be an issue.

However, advertised range on internet shows $1.05m-$1.08m! This was done without any discussion with or
knowledge of my sis, let alone consent or agreement from her. Very dodgy.
Sis wasn’t happy and instructed that the advertised range to be corrected/updated to be the same as SOI,
or even removed completely. However, advertise range was removed only 3 days before auction.
I think by that time the damage has already been done on buyers expectation.

Auction passed in and now agent posted a range of $1.08m-$1.13m, again with no prior discussion,
consent or agreement from sis.

She’s had it and wants out but is locked into a 60-day exclusive authority, another problem!!!

Is the above a valid underquoting situation? If so, can she use that as her leverage to terminate/sack
the agent and not pay any commission at all and go with another agent? Additionally, for the behaviour
of the agent who just ignores vendor’s requirements & instructions, lacks transparency & openness, and
does everything his way unilaterally without consent or agreement from vendor is just plain unethical
and non professional. Where/Who can this guy be reported to?

Thanks,
FXD