Try support:
Renew an Expired Minecraft: Bedrock Edition Realms Subscription
https://help.minecraft.net/hc/en-us/request/new?ticket_form_id=360001225811
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I payed for my old world to be renewed but instead they gave me a new realm and the old one is still expired
This issue is a billing/subscription problem that requires direct support from Microsoft, because account-specific changes (like correcting the wrong Realm renewal and restoring the old world) cannot be made through forums or self-service alone.
The appropriate next step is to contact Microsoft Support so the billing and subscription team can:
To contact support for billing/subscription issues:
For disputes about incorrect or unintended charges, support may also review eligibility for a refund according to Microsoft’s subscription refund policies.
References: