My Adwords account got suspended as well without a proper explanation as to why a few years ago.

After contacting Adwords support I received this response:

"Our support team is unable to provide any further information. Please do not contact us again."

I ran a campaign for a website for medical school students. Absolutely harmless and as far as I can tell in full compliance with the ToS! I can only assume that whoever checked/scanned the ad assumed I must be advertising medical items (which I was not).