Is there a collateral attack on a binding order issued by an administrative tribunal?

In respect of their submission asserting that there has been a “collateral attack”, the plaintiffs cite Garland v. Consumers’ Gas Co., 2004 SCC 25, for a description of the doctrine (at para. 71): The doctrine of collateral attack prevents a party from undermining previous orders issued by a court or administrative tribunal … Generally, it is invoked where the party is attempting to challenge the validity of a binding order in the wrong forum, in the sense that the validity of the order comes into question in separate proceedings when that party has not used the direct attack procedures that were open to it (i.e., appeal or judicial review). [Citations omitted].