Usual misinformation from Virgin.
Yes, you have to give them a STAC code for your EE contract to end.
From Virgin website
If you don’t want to bring your number with you, you’ll need a Service Termination Authorisation Code, or STAC.
When you use a STAC, your old airtime plan will be cancelled as soon as the switch completes. That means you won’t need to serve a notice period with your old provider or pay double the bills.
Just bear in mind that if you use a STAC, you won’t be able to recover your old number later.
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