Question: Some mates and I have the amount to cover the cost of an item but have a credit limit lower then the price. The purchase has a hard requirement that the payment method is a credit card. So, my mates and I put a negative balance on the card (I.E: The balance is 0 and then we pay something like 16,000 on it, making the balance -16,000 so we can make the large purchase putting the -16,000 balance back to 0).

Could we make the purchase using this method?

Answer: 
I'm not really clear why you don't just use a Visa Debit card for this purchase? I use Visa Debit for expensive purchases like long-haul international flights, hotels and health spas or whatever. It's really easy - I just transfer $12k or so into that account and then start spending. You can just put your $16k onto a Debit card and pay that way.

There are no monthly fees, and best of all, it is still backed by Visa just like a credit card. What I mean by that is, recently I was travelling around Europe and a dodgy vendor charged my card for 200 Euros that I didn't spend. The vendor didn't respond to my emails, so I complained to Visa and they reversed the payment. So you're just as safe using a Visa Debit as a credit card, and I never get stuck paying interest or late fees because I never owe Visa money. Debit cards are the best - I haven't owned a credit card in years.
You can possibly find a prepaid credit card. This is a card (in the USA, generally Visa or MasterCard) which looks to the merchant like a credit card, but from your viewpoint is one where you deposit money in advance, and any charges are debited against your existing credit. I have never used one, but if they work logically you should be able to deposit 16,000 of whatever currency you use, then charge that amount. Here's one list of potential vendors: <https://usa.visa.com/pay-with-visa/find-card/get-prepaid-card>