Steam Support does not contact users over the Friends network - decline Friends requests from users you do not know.
Steam Support will never need your password for any reason.
Ignore any password request you receive.

You may use Steam Wallet funds to purchase Subscriptions, including by making in-game purchases where Steam Wallet transactions are enabled.
Funds added to the Steam Wallet are non-refundable and non-transferable.
Steam Wallet funds do not constitute a personal property right, have no value outside Steam and can only be used to purchase Subscriptions and related content via Steam (including but not limited to games and other applications offered through the Steam Store, or in a Steam Subscription Marketplace).
Steam Wallet funds have no cash value and are not exchangeable for cash.
Steam Wallet funds that are deemed unclaimed property may be turned over to the applicable authority.