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.
They're not a scam but sometimes when the network is congested they can take a while.
As you can see on their site, they're saying that there may be delays of up to a few hours and you should have expected that as you initiated the trade. So just be patient, as long as you sent to the right address with the right instructions then there shouldn't be a problem whatsoever.
$1.5k is actually a small trade compared to the volume that they're handling on a daily basis. I've used them many times before without any issues. If your transaction is still not updated on the site, then go and ask support about it.