No rent received, no communication from rent agent

We have been battling with Everpro George for years with regards to getting insight into my son's share of rental from a house he part inherited. Last time they said they were sending the monthly statements directly to him, although he has authorised them to give us the information. He has not received rental for the past few months, and he went into his email and there are no statements. He is in Cape Town, and we are in the area, and when we go see them on his behalf, they are uncooperative. Apart from not knowing where the money is going, it's a shocking lack of communication.