You were banned for having too many recent punishments, although you claim you only have one active warning, which is true, recent punishments are anything given in the past two weeks, such as slays, mutes, and gags. When you get too many of these, you will get a ban. As shown below, after coming off a ban, for mass racism, you were given 5 recent punishments in a very short space of time. Even without the mute that you claim to be invalid, you probably would have been banned anyway.

You have had plenty of punishments and by this time you really should know the rules and know how to follow them. This ban was valid, fair, and won't be removed. When it expires I suggest you learn the rules because subsequent bans are only going to be longer.