Well there’s a lot to learn, but you can do worse than start with the ICANN dispute processes. And they are many: https://www.icann.org/resources/pages/help-2012-02-03-en

Country code registries have their own, and many apparent registrars are actually reselling Tucows or OpenSRS, both of whom have compliance teams that create significant leverage over resellers.

However, communicating them with them concisely and unambiguously requires care and understanding. Obtaining a result from the people who execute these processes means encoding requests in terms of their incentives rather than your own. Many people find that hard to do, especially people burdened by their own overwhelming sense of entitlement. This is of course advice for anyone engaging with an external bureaucracy, and the best way to internalise it, is to have run one.