Can I re-enter Thailand with a renewed visa after a trip to Siem Reap?

Hello! I recently renewed my Thai visa but I want to go to Siem Reap for a weekend. I've heard that you can buy a re-entry permit but I asked about this at the consulate in Penang and they told me that it's not possible (even when it's inside my permitted period), that I would have to get another visa in order to reenter Thailand (I'm from a country with a weak visa). Do you think that I would be able to re-enter or not? 🤔

Any help is greatly appreciated :D