If the ban appeal is denied, just try appealing again in 30 days. While permanent bans are permanent, sometimes Admins will reconsider if you haven't caused any issue and wait 30 days, sometimes longer.
so a permanent banned account still have chance to be unbanned if they wait 30 days then post appeal here?
There is a chance however it is not a guarantee that your appeal will be granted. A ban that has a specific timeframe will automatically expire, assuming that you do not later evade your ban. A perm ban however will not automatically expire.
If you try to evade your ban by posting outside of meta then you will likely quickly get your other accounts banned which will result in you waisting your money from either buying accounts that get banned or your "proxy tax" aka what you pay for registering an account with units of evil going to waste.