Cable loose, frayed, hanging, or one side lifting unevenly?
Garage-door lift cables work with the spring system and can be under significant tension. Do not attempt to reposition or remove them casually.

You do not need to know the exact failed part before requesting service. Describe what the door is doing, any sound you heard, whether one side is higher, and whether the opener still runs.
Send a non-emergency service request and describe what the door is doing.