I don't know if it is the case in every country, but if you sue without first contacting the airline, then VY could argue that you have made an 'unnecessary' lawsuit: VY would have paid you the money directly if you had contacted them (and you have no way to prove if VY actually would have paid you or not), and then the court might rule that you have to pay both your legal fees and VY's legal fees (which could be more than the amount of money due). Therefore, I think that you should definitely contact VY first, before suing them.

If you can't find any other way to contact them, send a physical letter to their corporate headquarters. Make sure to include all information they need in the letter.