and you shouldn’t be, so frustrating
looks like the scan they captured for that cert is the book they sent you, at least the back was already white
best you can do now is send it back in under the ME process (with detailed notes about both the label issue and white substance issue), hope it gets there and back safely and that whoever oversaw your book had a bad case of dandruff or just finished eating a powdered doughnut and it can be harmlessly wiped away and they correct the label and send it back without new issues
I don’t know how you can be convinced it isn’t the same book you sent … CGC QC (or lack thereof) is such a sad state of affairs these days
good on you to have taken or kept “before” pictures