There's no way to remove one particular subscriber from a channel. Someone who has paid keeps their access until the period they paid for ends. Here's what you can do instead.
Stop the behaviour
Block them in chat. This stops them writing to you directly.
Report a message, a comment or a profile that breaks the rules, and our team will review it.
Delete comments under your posts.
Close the channel to newcomers
In Settings → Management, Entry for new subscribers lets you restrict joining. Existing subscribers stay; nobody new gets in.
End all subscriptions
The same screen has Delete all subscribers, which removes everyone as their periods end. It's a channel-wide step, not a way to remove one person — usually it's the first stage of closing a channel down. See Deleting a Channel.
About the money
Subscription payments aren't refunded, to you or to them. Someone removed this way keeps access until their paid period runs out.
If someone is breaking the platform rules, report them and write to us at [email protected] — we'll take it from there.