Fortnite.com/vbuckscard

I bought a v-bucks card at my local gamestop this morning, and when i went to use it on the site ( fortnite.com/vbuckscard ) i put in the code, and when i clicked next, nothing happened. Help please

I'm trying to figure out how I can use my Microsoft rewards to get V-Bucks on PC. All the tutorials I found were mostly for Xbox, but I don't own an Xbox anymore. And other tutorials were US-Only.
That being said; would it be possible to redeem a 10 dollar gift card to Best Buy in Canada and use it on the .com (not .ca) Best Buy website to buy these and then redeem the code to the V-Bucks on the Epic Games Website in Canada?
If that doesn't work, what would happen if I buy V-Bucks from the Xbox Website, would I be able to use them on PC?
Or whats the difference between buying on the Xbox website than if I were to buy them from the Microsoft store?
Thanks

Article here:
https://www.cnbc.com/2020/07/24/epic-games-ceo-tim-sweeney-apple-crippled-app-store-with-30percent-cut.html

Apple has locked down and crippled the ecosystem

For a crippled ecosystem, Apple is doing pretty well, right? Last year alone estimates put App Store revenue at $50 billion (approximately 3 times the value of Epic Games) and growth was estimated to be 2.9% too - not bad when you consider that the App Store is 12 years old.

an absolute monopoly on the distribution of software

This is patently false - and he's doubling down here on the already false monopoly claim. An absolute monopoly is very different from simply a monopoly in that it is objective, not subjective. Absolute monopoly definition:
https://dictionary.cambridge.org/dictionary/english/absolute-monopoly

a situation where only one company, country, etc. produces and sells a particular product

Which clearly isn't the case with Apple. I mean Tim goes on to cry about Google and Android in the same interview - demolishing his own absolute monopoly argument inadvertently. Looking at the definition closer - if we're being kind and charitable and accepting Sweeney's butchering of the English language - then it applies equally to his own store and its exclusivity deals.

(an absolute monopoly) on the monetization of software

Tim is lying about monetisation, Epic Games found a way around the monetisation issue on Fortnite, by using the guidelines Apple themselves created - important to remember here, Fortnite is a free download on iOS - yet Apple allows gamers who purchased their v-bucks on other platforms to use them on iOS.
iOS gamers can even buy v-bucks gift cards on/offline, redeem them on the Fortnite website (while using their iPhones), and use the v-bucks in-game without Apple getting a cent.
https://www.epicgames.com/fortnite/en-US/vbuckscard
From the official Fortnite FAQ:
https://www.epicgames.com/fortnite/en-US/faq

Q: Are my V-Bucks bound to the platform I purchase them on?
A: Purchased V-Bucks are shared between PC and mobile if you've linked your account with your Epic ID. However, V-Bucks purchased on PlayStation 4, Xbox One, or Nintendo Switch are not shared between other platforms.

So Apple and Android permit v-bucks purchased outside the app to be used, but Epic investor, Sony, doesn't.

If every developer could accept their own payments and avoid the 30% tax by Apple and Google we could pass the savings along to all our consumers and players would get a better deal on items. And you’d have economic competition

To be fair, the article here is a bit shit. Earlier in the article, it refers to the EGS cut as a 12% fee, whereas here it doesn't challenge Sweeney when he disingenuously calls that same fee a tax.
Also, look at what he is really arguing for - he's calling for devs to be able to avoid the fee. He wants Apple to do what he won't do himself and that's while ignoring the completely different positions his shitty launcher and Apple's entire ecosystem are in.

I have two sons and two switches. One received a $25 / 2800vb card for his birthday.
On accounts.nintendo.com I have my account as parent/guardian and my two sons' accounts as supervised accounts.
When I log into fortnite.com/vbuckscard to redeem, I end up getting signed into my epicgames account that is linked I think to the parent/guardian switch account.
It then lists the current balance as 100vb and asks me to confirm deposit of the 2800vb from the card. I had both boys look at their switches to check their balance so I could ensure it was going to the one with the birthday. But neither balance was 100vb, one was 1350 and the other 150vb remaining from battle passes purchased at some point. That has my uncertain these vbucks will even remain in my posession!
I've been going back and forth with epicgames support through email and at this point doubt I'm even talking to a person. Any help is appreciated.