Testimony on Damage in a Bus

I was on a bus where the driver was driving with an open cargo compartment, and a baby carriage came flying out of it. The driver made a U-turn and the owner of the carriage alighted to pick it up. Now that person has called and asked me to write a testimony about the incident, given that his carriage was broken and the bus company is denying the incident. Am I allowed to write a testimony?

Dear …!
You are allowed to testify.
Even though this is not considered a testimony according to Halacha, the insurance company commits itself to cover damages with the intention to admit this kind of evidence.