Tampering suspicion during repair process of iPhone

On January 8, I took my phone to Best Buy due to water damage, and after an initial assessment, the technician informed me that a replacement would be necessary. However, without my knowledge or consent, my case was switched from a replacement to a repair.

Two weeks later, I was informed by Best Buy that the Apple repair shop had determined my phone was "tampered with" and therefore could not be fixed. I w have never tampered with my phone. I purchased it directly from Apple and have always used it as intended. This raises serious concerns that any tampering might have occurred either at Best Buy or during the repair process. Anyone have a similar situation.

[Edited by Moderator]