Mailbox size usage problem

Hi! I'm having a problem with a user's mail. In CPanel, it shows 542.22 MB usage. If I go to the user's directory /home2/clinicac/mail/centromedicodetorreon.com/almacen/cur, I have 545M and 1377 files with names similar to "1591827012.M167247P241295.servidor.sistec.com.mx,S=111736,W=114088:2,S". I think each file is an email (dated from Dec 19,2019 up to Oct 31,2020). But, when I go to the "webmail" (horde or roundcube), I only see 4 messages on the inbox. As far as I know, the /cur directory is the user's inbox, so why I have only 4 messages, but in SSH I have 1377 files using 542 MB? I have tried running /scripts/generate_maildirsize --confirm --verbose clinicac and also /scripts/mailperm, but the problem continues. The user only needs the "real" mails he sees on the webmail, but those other files are using space and filling his quota. Any idea how can I fix this other than manually deleting files before some date?