Milage tampering

Mileage tampering. We bought a Merc ML 63 from Umlanga CMH. 2 January 2020. Signed documents etc, when leaving and filling up at the garage just next door we realised the km's differ to what was advertised. Less than advertised. Whatsapp'd the sales person who in turn rep**** that a cluster change has been done. Said they'll sent us proof of cluster change. Other faults fixed which included sunroof, air intake pipe etc. Approximately 3 weeks after we left the dealership manager contacted us telling us to go and do our homework on the car. We contacted Mercedes Polokwane who confirmed that the maintenance plan revoked due to milage tampering and not missed services as per the sales agent initially indicated. Since been in contact with Hansie Louw (Regional manager?) of CMH who promised us he'll fly to Cape town to get proof of the cluster change. Then lock down hit. After lockdown we contacted Hansie again, who now says we were aware of the milage tampering. Luckily we have proof saying otherwise. Still awaiting response from Mr Jebb Macintosh who we've mailed today.