This experience is like what happened to me as well 5 days ago - I sent it 1 hour and 25 minutes ago - it still hasn't been sent.
I had a situation with bitcoin withdrawals from Coinbase not being processed (Pending) for a few hours, and then they just disappeared without a trace. Their support took 3 days to respond to my request, and then they blamed some kind of unidentified technical problems. I would not keep BTC balance on Coinbase for the life of me. This company is a total joke.