Appreciate the time you took to share your knowledge, many thanks from a rank amateur!

Apart from lack of water, I can't think of any reason why it should look like this. If it doesn't pick up within the next few weeks, I would be looking to take it back. Most garden centres have a guarantee ranging up to five years (Horticultural Trade Association). So keep your receipt and if your plant fails I would return it to where you bought it.

Did you wriggle out the roots from the original compost? I find that in our clay soil, if you don't remove some of the old compost then the roots stay in it and the plants does not do well.
Lack of water would soon stress the plant.

Over & Under watering can cause this problem, they need a well drained soil.
They will not thrive in alkaline conditions so I was told?
I have mine in a big pot, I used Ericaceous soil & I only water it with rain water
Good Luck with yours.