Hi Debabrata Bhattacharjee,
Think always, You are not the only one, who want a phone support. They work with the first-come-first-serve method.
The better way to contact the support is with an email at email@example.com
With the automatic answer including a ticket number You are in the queue. I'm sure they will help You. But there will be a first-in-first-out queue of tickets (problems and questions), too.
So we must be patient.