[matwood]

Businesses are almost always built on top of someone else. What you need to make sure of is that your financial interests are aligned.

[User23]

Which is to say have a contract that your counterparty can’t redefine freely.

[rs999gti]

Was there a contract or SLA for the free Reddit API?

If not, then there isn't much to complain about

[User23]

The terms of service are the default contract. Presumably it has a we-can-screw-you-whenever clause, but sometimes the corporate lawyers screw up and you can actually get them for violating their own ToS.