Not sure, if the above number is open for 24/7, but their road side assistance number is available 24/7.
Road side assistance number is 1800-209-3428. You can use this number in case of any road side vehicle issues and Fiat service will help you in a timely manner.
In case of any complaints or escalations, feeel free to email Fiat on the above given email address. Ideally, the support team will get back to you within 48 hours. But please note that sometimes it may even take longer.