Question to RPC/Wallet | Developer channel

[dkb]

Hello,
I want to make a platform for an altcoin and have already the wallet for it and it connected to my website (with rpc).
I would like users to enter their private keys and then be able to send and receive money.
When they do it, I would use the "importprivkey <key>" command.
But with that command, their address/coins also would be saved in my wallet.
How can I remove their address after it from my wallet?
Also what's the difference between accounts and addresses in the wallet (it's under "debug window" -> command "help")?

Last question: Is there a developer channel like slack channel or telegram group where I could get help from?

Thank you for answers!