@kalel It could be that your Zoom Phone admin has enabled this setting "Anonymize PII from Dashboard and Call Log." for security compliance/privacy purposes.
This is an account level setting can be accessed by following instructions here. With this setting enabled, it allow Zoom to automatically anonymize PII data from dashboard and call log after the specified number of days.

Your other options:
1. Subscribe to Zoom Phone Reports, use third-party apps or develop your own to parse the data you need;
2. Use Zoom Phone API for call logs here and again use third-party app or develop your own app
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