Guardia di Finanza is a law enforcement agency. They won't share information about whatever they are investigating. Don't rely on this as the actual cause of this problem. You should first exhaust all tracing efforts. The post office should do an end to end check on their SWIFT or SEPA system. If the post office used a correspondent or intermediary bank, that bank should be contacted to check on the whereabouts of the money. The post office is not a bank which leads me to assume they might have used a commercial bank to execute the SEPA transfer.

These are large amounts so you should stubbornly investigate these SEPA transactions. They can't just disappear.