Well, to shed insight on Azure.
1. Phone number is required to minimize fake/bot/fraudulent use accounts.
2. Credit card is required in case you want to immediately scale up, and also, used as anti fraud as depending on the card used, and address is used to judge you as a customer and whether or not you should be disabled immediately upon account creation.
Credit cards first six numbers are the BIN, or bank identification number, these are used to sort whom the issuing bank is, what type of credit card line, and whether or not it is a virtual or such.
These are compounded to give you an antifraud score. Address and connecting IP address help too.
So that's why it was denied, but for a company like Micrsoft, their billing practices are very much streamlined and not so hidden vs other companies nor do they introduce "tricky" language such as Adobe's yearly contract, payable monthly SAAS.