From their warranty clause for Denafrips, it is clear that they have no control over the repair time depending on the complexity, so escalating it on social media may only worsen the relationship.my experience with HPZ so far has been good. a niece had an issue with a headphone and they replaced it with the newer model under warranty.
As above your best option is to create a twitter/insta/facebook acount and post it to them. it always works better than anything else.
It is better to keep up the communication internal to the company and move to other options if Headphonezone starts to shy away from its commitment/promises.
However, it is prudent to simultaneously email Vinshine as they are the backend for the service support to Headphonezone. It could help in a faster resolution of he problem.