The amount charged for the sponsorship tier is inconsistent with what was expected.

[libukai]

I chose a sponsorship tier of $15 per month, and on the subscription page, it showed that I still needed to pay $4.93 within this annual period.

However, when the credit card was charged, it deducted $156.33.

I'm wondering what happened, anyone could help explain it?

[squidfunk]

Thanks for (trying?) sponsoring!

The $4,93 is the prorated amount for a month, so your billing cycle would be due in 10 days or so. However, I'm not sure why GitHub then switched to yearly billing. Could be a bug in GitHub's payment processor. I'm sorry for the inconvenience, but we can't help you with anything payment related. I recommend writing to GitHub support, they are helpful and quick to respond.