Hilariously (and I did not yet close the loop yet) have a comment amount Right to Erasure with Smarty.
Having had a major disagreement with their parent, well Three one of my retaliation measures was to leave Smarty. (and Three at contract end also)
I followed the Smarty website but it would just not close my account down.
So I messaged / email using right to erasure.
Then followed lots of emails to a supposed diligent offshored IT team.
I reminded them that after they sent me the ALL DONE email they would need to delete my details.
So they told me they deleted my account.
HOWEVER they have subsequently sent me numerous courteous emails, so they clearly still have my information!
I intend to close the loop by emailing them in a week or two. Hopefully they will answer something like: Who the hell are you