If you have a negative balance, it may be due to a payment problem involving your financial institution or payment provider that caused a purchase to be automatically refunded, or you may have requested the refund yourself. If your Platinum balance goes into the negative due to a refund, you will not be able to log into the game using your account until the negative balance has been restored to a positive level. Please contact your financial institution/payment provider directly to resolve any issues with them. Also, please know that Warframe does not support the reversal of chargebacks as it is not possible to transfer any funds back to Warframe when they have already been removed from us. If you wish to address your negative Platinum balance by purchasing Steam Packs, you will need to contact Warframe Support for assistance with this.
Please also note that the in-game trading system is intended only for equitable trades between players, not for trading large amounts of Platinum between accounts. If you purchase your Platinum from a legitimate source, it will be deposited directly into your account ie you will not need to provide access to your account to anyone, nor will you need to make a trade to receive it.
If you have purchased Platinum through an unofficial 3rd party site or from another player there’s a good chance the Platinum was not legitimately obtained (for example, it might have been stolen from another player’s account, or it might have been purchased using fraudulent credit card information). Should an investigation find that you received Platinum from one of these fraudulent sources, it can and will be removed from your account. Please contact Warframe Support and we will be happy to work with you to resolve the issue and get you back into the game as soon as possible.