Mailed April 11. Sent with initial payment money order. Have not received anything in mail or any deductions on bank account. Online IRS not an option. Suggestions?

I tried calling them today about it, but kept on getting told to call back later due to high volume. I'm fairly certain they didn't get my return and it wasn't filed - my TurboTax homepage will still says it's "ready to mail". Anybody know where to go from here, apart from calling and hoping they pick up?