Can I pause the SLA timer?

Absolutely! If you're using HubSpot, you can "pause" the SLA timer for any pipeline stages that you might not want to count toward your SLA target - for instance, "Waiting on contact".

To set a stage as "paused", click "Pipelines" in the left hand sidebar, then "Edit" next to the pipeline you'd like to change:

Then, toggle the stages you'd like to be "paused" to be inactive ("Pause" icon) and click "Save".

Now any tickets in the "Support Pipeline" will subtract time spend in "Waiting on contact" from their SLA targets.