Look you can deny it all you want, but this is most likely an alternate account of yours. For the banned IP the only people that have ever connected from it are you and this Venomous person. Most recently you disconnected from our servers 15 minutes before they showed up and got banned, and then afterwards the only connections from that IP have been you. Even if this is actually a VPN issue, it is highly unlikely they'd give this person the IP you were using for this short amount of time and then give it right back to you.
"But I don't know who this Venomous person is!" you say. OK fine, let me go look Venomous up. Oh, they've only ever connected to us twice, once from the IP you were banned on, once from another IP back in February. Let's see who else connected from that other IP. Oh look, the only other person that connected from that other IP was...you! Back in February! And there was only about 90 minutes difference between the connections!
Now what are the odds that this person that you have NEVER SEEN BEFORE has connected from TWO DIFFERENT IP addresses that you just so happened to also connect from, and both times they were within short time frames of each other?
You're caught. Take this as a life lesson moving forward to not cheat on anything in the future.