In case if instance is abusing resources of a machine (like CPU, memory, disk, network) the operator is responsible to take proper actions. Here the operator can learn the general approach for such case.
Locate the relevant Support Request related to the instance abusing the machine.
Find the cause of the problem, which can be one of memory consumption, disk usage, CPU overuse or any other resource provided by the machine.
Contact the user by creating 2 new events (1 "Mail Message" event and 1 "Web Message" event) on the relevant Support Request. If the problem does not impact the machine fully (like disk filed), ask the user to fix the problem in 24h. Wait that time before Take actions.
Otherwise inform the user that actions are being taken, and he shall fix the instance as fast as possible.
Contacting the user consist of:
Stop the Hosting Subscription related to the Support Request.
If it is needed to do some clean up (like freeing disk space), execute it and inform the user about actions taken.
Assure that machine is running normally.