I have requested (in many emails beginning Jan 2018) that Coinbase provide a method that allows me to update my secondary email (which bacame invalid in 2017) in order to transfer funds out of my LTC Vault and into my LTC wallet.
Finally Coinbase stated they would reslove this issue in an email 3/9/2018. I have not received any Correspondence since then.
My funds in the LTC vault are not available and they have lost most of their value since Jan 2018. I would not recommend using their services.