Snapchat over the new year had an ” issue ” with over 4 million accounts having their user names and phone numbers leaked online.
To see if your account was compromised there is a tool that you can use that will check if your details were leaked.
Click here for the tool: GS Lookup SnapChat
For more details on the leak check this Mashable Article : Use This Tool To See If Your Snapchat Account Was Compromised