I would agree with your thinking that I only bought a regular gold membership - BUT - since I paid in Dec? I've been able to participate in Premium game content. Until yesterday.
You need to use that Refunds link posted on the previous page by Corder and myself.
Messaging Billing Support will get them to check your account and diagnose what has happened.
Navigation:
Contact Us -> No -> Jagex/Steam -> Request a Refund
It might seem odd contacting via the 'Refunds' support page when you just want the Gold Premier to work but Billing Support wants all contacts re Premier Club to arrive via the Refunds contact point.
If you no longer have premier artefact perks (check bank, diango), please submit a support ticket:
Request a refund
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