Since what you are advertising is not an ICO it should be OK. But to be on the safe side you might want to contact facebook about it before doing so. Also, you should know that facebook has partially reversed its cryptocurrency ban. Some advertising is allowed but ICO ads still aren't.
Social media behemoth Facebook Inc. (FB), which had banned cryptocurrency advertisements earlier this year, has partially reversed its position. In a post on its site, Rob Leathern, Facebook product management director, stated that the advertisers wishing to place cryptocurrency-related ads on the service would have to submit an application to an internal team that maintains a list of pre-approved advertisers. The application would ask them to detail specifics relating to the product, such as whether it has been listed on a public stock exchange or whether it has obtained licenses. Ads for binary options and initial coin offerings are still banned on the service, however. (See also: Facebook Bans Ads For Cryptocurrencies And ICOs).
Source:
https://www.investopedia.com/news/facebook-partially-lifts-ban-ico-ads/