Secretary certification is invalid?

We are buying a lot from a company. One of the board member gave us a notarized secretary certificate certifying the board resolution that majority of the board approves the sale. However, we found out thru one of the employee that the secretary already resigned since last year. Lot title is clean and we've confirmed the name of the board directors per SEC documents.

1. Shall we continue this transaction knowing that the secretary certificate seems invalid? I think the company don't want to nominate a new secretary for whatever reason?

2. The board resolution should be signed by all or only majority? How can we check if their signatures are valid?

3. Is it advisable to transact via bank's escrow. It will costs us around 50k pesos (1%).

Thank you.