If he had broke more than one rules, you should have listed them in the ban reason. The 7 days ban is too long for leaving the server after getting muted, moreover as the server had mute him back after he connected to the server. This case is not same as the attempt of ban evade he did, he intentionally used VPN( which is also against the rules ) when he tried to evade the ban.
I'll unban him for now as he was already punished for insulting staff( which i believe, it's in this report:
http://ec.vc-mp.co.uk/index.php?topic=3481.0 ) and server had mute him for mute evading( as stated in his post ). You may ban him again if you have evidence of the other rule break he did/do.