He also didn't describe much of any of his technical requirements. I'd say it's a fair assumption his setup was enough different to cause an issue. Whether or not that's a fireable offense is up to the company.
The weeks of shitty service beforehand are what really did it.
If you're looking to upgrade in the future, you might be much better off throwing a dedicated server at the problem and setting a nightly backup to S3. Also, thank you for posting.
Monthly cost is about $40 ... unless you count my time.