There is no way to limit the amount of DMARC report analytics. GlockApps receives all DMARC reports as far as you have the DMARC record pointing to GlockApps in the domain’s DNS.
The over-use fee is $10 per 1 million of an over-limit volume.
If you don’t want to pay an over-usage fee, you can do this:
1. Remove the DMARC record pointing to GlockApps for the domain which causes the volume to exceed.
2. Upgrade to the next tier or create a custom plan that covers the necessary amount of DMARC compliant emails. DMARC non-compliant emails are not counted towards the total volume, so a sudden spoofing campaign will not cause the plan limit to exceed.