Right now, the community is supported in English, so I hope you don't mind me replying like this 🙂
Sounds like you could have multiple Spotify accounts created with your information. You can make sure you have the correct account following these steps.
At the moment, you can only use a payment method to redeem a promotion once. This means that if you've used the same card to get the 30-day trial or a different promotion in the past, you won't be able to use it again on a new account.
All the best.
“Music acts like a magic key, to which the most tightly closed heart opens.” ― Maria Augusta von Trapp