Try their website first via email and if it's ignored, try calling them.
You should be able to go on the website and/or call reservations and give them your confirmation number and then request an email. Be sure, that if you correspond with them, that you send all correspondence, registered, receipt requested. We made a cancellation via USPS and have a postal receipt, dated and signed for, before the expiration date.
I would try call Sheraton Vistana Resort Villas reservations and ask them what the process is for the cancelation confirmation and request the copy by email or mail good luck.
No idea, I would call their Check-in office and see if they can e-mail it to you. I was just their for a visit, unsure about their process and account policies.
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