Just saw this article:
I’ve been having a hard time with PayPal too. Recently, all PayPal transactions were automatically being charged to my credit card, even though I had enough money in my PayPal balance to cover them, and even though my settings said they would use my PayPal balance first. I sent them a support ticket, got a response saying someone would reply within 24 hours. A few days later all I got was a FAQ. The problem continued, so I removed my credit card from my PayPal account.
Okay, so I just tried to buy some Huel using PayPal, but it is asking me to add a card. NO! I have the money in my PayPal balance to cover it, I don’t need to charge it to a card!
What is the point of having money in my PayPal account if I can’t spend it?!
I’ve just sent another message to PayPal, so I’ll see if I get an actual response this time…
Paypal are not in my good books at the moment. We might be switching to amazon payments.
Paypal pretend to be a Bank but in fact they act like a much of mob bosses.
If you have any issue whatsoever forget about it, their customer services are non-existant.
It’s all sorted now, but I had to search online to find previous people who’d had the same problem to figure out what was wrong.
It turns out it was because my balance was in $USD. You can’t spend one currency for purchases in another currency. I genuinely never new that. Still, learn something new every day.
So I had to withdraw the money out into my bank account, at which point it gets converted into £GBP. Then I bought my new batch of Huel using PayPal, which gets charged to my credit card, which I will then pay off in a few weeks with my current account…and so the money gets shuffled round and round in circles 
Ordered the new pineapple and coconut flavour, so it will be interesting to try that. I was glad to see the strawberry flavour is back in stock too. I was tempted to get that again, but money is a bit tight so I don’t want to get too spend-happy.
not sure when they removed the option but years ago it was possible to open a balance in another currently and transfer it between currencies. At some point I had USD, GBP, EUR, and ILS balances each with its own balance.