1) Demand a replacement or refund from the vendor.
2) Get a bottle of Kelpak* and mix up a 1% solution with tepid water..
3) Immerse the entire plant in the solution for a couple of hours..
4) Pot it up however you intend to grow it, long term, and water it in with the solution.
5) Invert a clear plastic bag over the plant and pot to trap humidity, and put it somewhere warm and with no direct sunlight (we don’t want “humidity tent” to become a “broiling bag”)
If it needs water during the next month, use the Kelpak solution at 1:250.
* C&C Orchids in Hamilton ON resells it in Canada via Facebook. If you are close enough to the border, I can save you money and ship it for free to one of those “shipping services” and you can pick it up.