[caw]

In Slack's case, yes they're proactive. But this is not the norm when enterprises violate their SLA.

If a service outage is particularly bad, some providers will be proactive and reach out with credits. This is rare.

In most other cases, the company relies on you to contact them and claim that they were out of SLA, at which point they'll investigate and give you back a pittance of what you paid that month.

The claims is normally a fun go-around process of pointing fingers.

See for instance the Amazon EC2 SLA - https://aws.amazon.com/compute/sla/. In order to even begin to claim it, you need to be running in 2 AZs. You must provide evidence in a ticket. Your service credit will be either 10% (99.0 - 99.9) or 30% (< 99.0). Whether you were down for 1 day or 14 days, it's the same SLA credit. The credit is applied to future service, may be applied as a refund to the current bill at their discretion.