@Olasunkanmi Adu Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
Based on the error, You may experience an issue or error in which a credit/debit card is declined at Azure sign-up in the Microsoft Azure portal. refer to the suggestion mentioned in this article. If the issue still persist, would recommended to contact azure subscription support team it's free, and it's the best choice for your scenario
Please let us know if you have any further queries. I’m happy to assist you further.
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