I need to close my community account

I can't find a way to delete this account. I was forced to sign up to this community because someone else had used my email address to associate with their Boost account. I live in the UK, not the US, so there's no point in my having this and I also have concerns around data protection, privacy and data sharing in a company whose data protection policies are not built around the EU GDPR.

Please can someone tell me how this community account can be closed and how I can ensure that any associated personal data have been securely deleted?