I am 100% sure I sent transactions with testnet4 and it was confirmed on the blockchain
Been there, done that:
I deposit 0.01 (testnet4 to be clear), it keeps counting down from 60 minutes to zero.
But:
I'm starting to think you're mixing up testnet3 and testnet4: your Beta guide linked to several testnet4 faucets, which made me think that's what you're using, but other parts of the guide make it look like you're using the old testnet. You should probably use the most recent version, which is much easier to get.
We are using BTC Testnet v3.