Bought Allianz annuity and want OUT

[Crackle]

I signed up the for the Allianz Endurance 15 annuity on Monday, October 22nd and it was setup on the 24th. Signed the receipt last night - the 20-day free look period should officially begin today. I plan to send (fax) notice of my decision to opt out within the next couple of business days . . however, I want to know that they actually receive the notice. Is there a recommended strategy for confirming this? Simply call back a day later or something? :confused:

Thanks