I've sent ETH to convert to Bitcoin, and it's been stuck at "awaiting deposit" for the last few hours. I've used them before but for much smaller amounts. I normally send around $500 max but this time I've send around 1.5k to be converted into Bitcoin and this time it's taking forever to deposit when other times it's been instant.
Can you post your ETH tx id here so that we can check how many confirmation it have already got, if it is already confirmed than you should contact shapeshift support to process your exchange.
shapeshift is definitely not a scam as I have also used them for many exchanges before like many others.