You are entitled to a
full refund less any "service fees" as the Netherlands is in TC2:
16. VOLUNTARY CHANGES/REROUTING/PENALTIES
...
(b)
Cancellations and Refunds(1) Prior to departure
(a) Origin TC1
(1) Before ticket issuance - full refund
(2) After ticket issuance - 10 percent of ticketed amount
(b) Origin TC2/3
No penalty
...
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Local service fees may apply
As for the refunding process, that depends upon the entity (Agent?) you purchase through.