I too have preordered EPs from CDKeys in the past and not got the bonus content. For a couple of packs (I think it was Growing Together and For Rent) I later bought the bonus content separately from them, and it worked fine.
But I agree that the info this time on the CDKeys website seems to suggest you will get the bonus content. I wonder if this is a change? I was surprised to read this on their website as it seems different from what I remember it saying before:
Where possible, we will try to ensure that any pre-order bonus content is included within the product if mentioned on the product description page. However, there may be occasions when the bonus content is only available while stocks last and is not always guaranteed. Customers who pre-ordered are advised to regularly check their orders page to ensure they receive the bonus content as soon as the keys become available.
Even with this wording it’s still not guaranteed, though.
