It tells you on the club website-
I would like to cancel my active MyGers Membership. How do I do this?
MyGers Members who wish to cancel their Membership should complete the MyGers Membership cancellation form available here. This should be returned to
mygers@rangers.co.uk.
Cancellations within 14 days from purchase will be refunded in full. However, the Club is entitled to a refund or return of any Membership benefits you have received during that time through your Membership privileges. This includes any match tickets you have purchased through your Membership privileges.
Cancellations after 14 days of purchase will not be entitled to a refund.