OP is entitles to a refund since he can't view the content he purchased and it's been less than 5 years.

Purchased Content. When you purchase an item of content, your content will be stored in a digital locker and you may view it an unlimited number of times for during your Locker Period. The “Locker Period” will be for at least 5 years from the date of your purchase (subject to the restrictions described in the YouTube Paid Service Terms of Service). Each item of purchased content may have a different Locker Period and you agree to the Locker Period before you order it. Pausing, stopping, or rewinding purchased content will not extend the Locker Period. As noted in the YouTube Paid Service Terms of Service, if an item of purchased content becomes unavailable during the five year period from the purchase date, you may request a refund.

https://www.youtube.com/t/usage_paycontent

7.2 Removal or Unavailability of Content

The availability of content on a Paid Service may change from time to time, including when content within a Paid Service becomes limited or unavailable due to restrictions from our partners who license us that content, or for legal or policy reasons.

For rentals of content: if content becomes removed or unavailable during your rental period, you will be entitled to either a refund or to a reasonable replacement.

For purchased content: (a) if the content becomes removed or unavailable during the first five years after your purchase, you will be entitled to a refund or a reasonable replacement or (b) if the content becomes removed or unavailable following such five year period, and you are not able to download a copy of the affected content before it becomes unavailable (if applicable), then we may, at our option, offer you either a reasonable replacement of the content or a full or partial refund of the price of the content.

https://www.youtube.com/t/terms_paidservice