EC excluding OC member’s participation in AGM

In the ACT, a unit owner must give an address for correspondence which must be kept on the unit roll. The OC is only required to send meeting notices to the address on the roll. It is possible to opt for electronic notices instead (IE by email). I expect it is similar elsewhere. 

Anything else, such as arrangements to make phone calls, would be beyond the requirements for proper meeting notices and falls into the category of an informal or courtesy arrangement. If the formal requirements for meeting notices have been met, I doubt the Office of Fair Trading would be interested. 

I suspect you would not get far unless there were something in writing from the person wishing to attend by phone such as a request to the managing agent or the chair to attend by phone as per previous arrangements made reasonably in advance of the meeting. 

The office of fair trading is more likely to be interested if the outcome of a close vote could have been different with one more attendee. 

I am not up to speed on whether NSW (where I presume you are) has anything on attendance by phone. In the ACT the legislation is silent on that and only provides for attending in person, by appointing proxy or lodging an absentee vote on notified matters.

In the ACT, in the absence of legislation or any case precedent that I am aware of, I would say it is up to the chair to decide whether to accept attendance by phone. A fair reason for not accepting would be insufficient notice of the request to enable conferencing facilities to be set up. 

In my experience, people unable to attend but with an axe to grind have appointed a proxy and provided that person with a list of questions.