There are 2 versions of billets - a free community version and a purchased commercial version via website subscription. If u are looking for a helpdesk give the community version a try as it shows off the core features of the billets system and is free. The commercial version does have LOTS more features built in including frontend ticket management and in my opinion is worth the $49.99 price tag.
During install I contacted the dioscouri support a handful of times and each time got fast and useful responses. The only reason I have not given 5 stars is that I would like to see more flexibility in the frontend settings, such as more in depth layout control.