Fixing what you broke matters more than explaining why you broke it.

Explanation serves you and repair serves them. A reason, however true, leaves the broken thing exactly as broken as it was, and it asks the other person to spend their attention on understanding your position. Fixing it changes their situation. That is why people who have been wronged remember the repair and barely remember the reason, no matter how reasonable it was.

Work out what the actual damage is and deal with that first. Replace the thing, pay for it, redo the work, make the call you avoided. The explanation can come afterwards in one sentence if they still want it, and often they will not.