Zendesk is software used the Support team. It's got a lot of functionality, namely being able to identify and collate other tweets from an individual to aid more effective and informative action. Presumably the reply in the OP was to this tweet: https://twitter.com/ShannonDebest/status/1256403458296557573?s=19.

In this instance the person in the tweet claimed to be hijacked and banned. The link in the tweet would allow the ban to be appealed and quashed (if it was incurred by a hijacker).

Yocairo

To hijack this comment, why isn't there a proper way to contact Jagex support for things like this?

If you head to the Old School website and click Support you'll be taken to the Support Centre. If you type 'ban' the article they linked in the tweet will be the first thing that pops up. Clicking the Appeal button will ensure it's checked by the Support team.