First class mail USPS label option missing. Is anyone else having this problem?

Hi all, new seller here.

When I setup a shipping template, there is no USPS First Class option? Just Ground and Priority? How do I get the option for First Class to show?

Amzn allows orders under $10 to be shipped via first class letters. This allows customers to purchase cheaper items without being hit with $5+ shipping fee. Amazon then sends these customers an email 14 days later stating "package may be lost" which Amazon has no way of knowing. This creates endless refunds and or a-z claims. My question to amzn is this... with all your endless resources, can't you simply make a deal with usps for standard envelopes with tracking like your competition has?