If the proxies exist, for them to be valid they would need to be signed by the persons giving their proxy but not necessarily the proxy holder. Plenty of owners commonly just give their proxy to the “chairperson of the meeting” so the proxy holder may not necessarily be aware of this ahead of time. The proxies should however be disclosed at the opening of the meeting so it is clear of voting rights and quorum calculations.
For the proxies to cast a vote on the appointment of the strata managing agent these voting instructions must be clearly indicated on the proxy form. If they were not, then not enough owners were voting on this motion for a quorum so the decision should be invalid.
At the meeting, two persons must have been nominated to sign the agency agreement and this must have been executed and a copy given to the secretary (or other nominated owner) within 48 hours of the execution. If this was all done, you may need to look at the terms of the contract regarding termination, specifically with respect of negligence.
A strata search should answer most of these questions in the first instance.