https://twitter.com/RevolutApp/status/793148217110228992
It can be top-up with credit/debit cards or sepa or bank wire.
The bank account isn’t nominal, it is a shared account. The user must enter a code/number in the reference when he makes a deposit from another bank.
Also, the bank account that the user uses to make the deposit must have his name.
It supports eur/gbp/usd currencies.
With the internal transfer system (that works like paypal), the receiver user must be registered on the app with his own phone number. (so both users must be registered)
It is possible to add a note on the transfer, but it’s not mandatory.
It is also possible to make a “bank transfer” to the user himself, another person, or to a business.
Here you can find the fee:
https://revolut.com/faq/gettingstarted.php?cat_id=10&faq_id_according=52&cat_name=Common%20Faqs#parentVerticalTab10
The support said that the chargeback isn’t possible … 
From the support:
Me: if someone will register a stolen card, and then he send the money to me, if the real owner will request a chargeback, where are you going to take the money? even from my account?
Support: Hello!
Me: hi
Support: Let me explain
Stolen card to hi Revolut?
Me: and what if he say, “oh they have hacket my account!!”
If he as done a top-up with a card, a stolen card.
and then send some money to me
I want to know how much I’m safe from a chargeback
Support: Our security procedure won’t allow to top up using stolen card
The first thing is a card authorisation
Me: what if he asks mastercard/visa for a chargeback because he is an idiot or a thief?
I’m worried that something will come back to me if I’ll use your app to sell something.
Support: we are initiating a chargeback
Me: and a thief/lamer/hacker will use it against me
Support: What is more, Mastercard won’t let starting a process without confirming it
Me: so, I should be safe …
Support: We partner with Paysafe Financial Services, a global provider of online and mobile payment processing services, and use their secure payment gateway to transact on behalf of our customers.
It is safe.
Me: Maybe you already know, but even paypal should be safer, while instead it isn’t from the point of view of the seller.
Is there a limit of how much an user can transact on your internal transfer system?
now I can’t remember, can a not-confirmed user top-up his account with a card?
Support: Using Revolut to send, spend, withdraw and exchange in a foreing currency is free for the first £5.000 / €6.000 / $6.000 (or equivalent) per calendar month. A 0.5% fee will apply to any further cross-currency transactions performed during the same calendar month.
Card spending is limited to £30.000 or equivalent per year with a sublimit of £5.000 or equivalent per 96 hours meaning that you cannot exceed $5.000 or equivalent in card spending in 96 hour period. Cash withdrawals from ATMs are limited to £2.000 or equivalent per day.