Did you make sure you are using Binance.us and not Binance.com?

Binance needs your number because they will send you your one-time verification code there.

Anyway, if you have a payment option other than a debit card, say, PayPal, you might want to do the buying here. Please check the Currency exchange board. There are 1:1 ($1 of fiat: $1 of BTC) offers there. That way, you could avoid buying BTC with high premium from exchanges. Please use escrow.