mutantducky wroteBy rule could the refs have called a T? .
No. You're skipping a step. First, the official should have granted the timeout. There is no provision in the rulebook, casebook, or the mechanics manual, for an official to ignore a legal request for timeout out just because the official knows that the team has used their last timeout.
Second, after the official scorekeeper confirms that the team has used an excess timeout, the technical foul is charged, but only after the timeout is granted, and used.