How do I dispute a billing error on a CSP invoice?

Start with your CSP partner directly — since they issue the invoice, they're the first point of contact to review and correct billing errors, and they have access to the underlying Microsoft usage data needed to investigate. Most legitimate billing discrepancies (like a resource that was decommissioned but still billed, or a licensing count mismatch) can be resolved at this level.

If an issue genuinely can't be resolved with your partner, Microsoft does have its own escalation paths, but partner-level resolution is almost always the faster route since they have direct account access.