This situation can happens to anyone that while performing any task in his Gmail account he has deleted any one of its contact details, but later realized that how much important that address was. Now if you came across this situation and thinking that now it is not possible to recover those contacts then let you know that it can be reversed if you want to restore them with in a months period span.
Steps to restore Gmail Contact list:
1. First of all login to your gmail account and click on more option from the top right corner of the Gmail windows as shown below.
2. Now click on Restore Contact from the context menu that appears.
3. In the pop-up window, select specific time / date to revert your Contacts list. You can restore contact to any specific days, hours, minutes using custom option (upto 30 days).