I have contacted Guild Wars 2 Support for this exact same problem.
I had a total of 882750 WXP stored at bank. The support can’t do anything against the Dev team decision.
The only way to get in touch with the Dev team is to post on this forum and hope they dare answer.
They are probably good coders but it seems they don’t care at all about players. Now I have over 9 stacks of useless and ridiculous boosters sitting at bank.
Yes, Dev team, stop hiding behind forums and take back your wonderful boosters and give me back all my WXP and rank chests.