Vatika Group — Vatika professional point office unit. Rental management and fraud

I am a 95 year old widowed lady living on my rental income from a property my late husband bought for our old age. The unit was bought from vatika group and the vatika group has the management, leasing etc. Of it. They have been arbitrarily deducting charges and putting on various fees and charges.. Have leased the unit at a lower price without approval.
My son has come from abroad and tried to help me by contacting the vatika group on phone and email. The phones are never answered as are the emails. What recourse do we have to resolve the various issues.