How does a refund work if I settle my balance?

Description

I’ve just bought a TV for £897 using PayPal credit with a credit limit of £1,000. I’m looking to return the TV to buy the next model up which is £1119. Unfortunately, the promotional period to buy the TV ends 30 September so I don’t have time to wait for a refund from Samsung (5 days) and Paypal Credit to update (3-5 days). If I do, I will miss the 20% off promotion.
If I was to use £1119 of my incoming wage in a few days to settle my balance and ‘top up’ my PayPal account with a few hundred to account for the higher TV cost, would I then be able to place another order using PayPal credit for the higher cost TV?
Really keen to use PayPal credit for the 24 months 0%.
I haven’t explained the best I could have, so if anyone has any questions I will explain further. I’d be thankful if anyone could shed some light on this, want to get the TV ordered pronto!