It seems that Deezer do not support yearly subscriptions and a workaround is to purchase a Gift Card however these are only available for Premium and not HiFi. I thereby suggest:
1) A more flexible subscription model than per month e.g. 6 months and 1 year for any plans
2) Gift Card for HiFi or just generic gift cards that are not bound to a plan, instead when a gift card is redeemed the money are added to your account
/Adam
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Hey everyone,
We're happy to announce that we made this an option for all of you who want more for your buck 
https://www.deezer.com/offers/annual-plan-hifi
Check it out! 
It doesn't work now 
The Family tier includes HiFi streaming in many countries now at a slightly higher price than before. Probably that is why the old link does not work anymore.
Meanwhile I get forwarded to this page when clicking on your link:
https://www.deezer.com/en/offers
It looks like this:
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.