Again - not offering any advice, but sometimes electronic devices make noise. I had a PWM BJ Box Mod that used to whine when it fired. The pitch of the whine increased as you increased the output voltage. Perfectly normal.
Not saying it's the same, and certainly not saying the "ticking" is OK - but electronic noise happens.
If Vaporesso says it's dangerous - I might listen, but the reseller saying it's dangerous might be an err on the side of caution for liability reasons.