Have you done your research?
Does the provider have a history of ads, recommendations?
Does the provider have a website, multiple ads across multiple platforms, social media, a fan site?
A reputable provider isn't going to runaway with your deposit. Follow their directions. They have rules and guidelines in place to keep everyone safe and have reasons for doing things a particular way.
It's a lot of time, money and effort to build a business of integrity for this industry. We are constantly fighting laws around the world to maintain our presence on the internet. A provider with a history isn't going to ruin their hard work by taking your deposit.