Well, if the casino representative did not clearly write that a VPN is allowed I would not use it. I haven't seen it officially stated on any site, it's probably not legal, but many crypto casinos allow it, but again I say you have to have a confirmation about it. If it is not from the forum but from support, I would take a picture and archive it somewhere just in case, it can help if there are any problems.
I did the same thing in the past. When there is no clear information about VPN is allowed or not in the terms page, it is better to ask support and if the support answer that it is allowed, I take a screenshot of the chat or download the transcript if the casino provide this feature. This can be something useful later if the casino said that using VPN is against their terms.
I used to use VPN to play in some casinos and I never had any problems, but again I didn't win anything big. So who knows, we should be careful anyway and have some proof that casino allow it.
Me too, when I was still actively gambling at duelbits, I used VPN most of the time. I did not win big too, my biggest withdrawal from duelbits was around $3000 and there was no issue at all.