First of all, please excuse my off topic but I realy need help and I don't know where to ask for it.
How can I prove that I installed Android 10 update on my phone???
I have an Asus Zenphone 5Z and, in october 2019, I had the following problem. No signal for cellular conectivity. The phone detected the sim, was asking for sim pin code but no connection after that (no mobile data, no calls). Everything else worked just fine (wi fi, all apps, everything). Tried both sim slots, diferent sims, nothing worked.
I sent the phone in servce. It was repaired. They fixed by changing the mother board and the fingerprint sensor, as they specified.
Now, the real problem comes.
This month, January 2020, exactly the same problem happened again. I sent the phone back in service like first time. They sent it back fixed, only that, this time, they mentioned in the papers "The mentioned faulty is not confirmed".
So, my phone came back fixed but they said it was nothing wrong with it.
But, I figured out that I sent the phone with Android 10 update instaled and they sent it back with Android 9. That meand they did resofted the phone, changing the firmware.
I contacted them to ask why they said "faulty not confirmed" but they resofted the firmware. They said they did nothing and I have no proof that the phone was sent in service with Android 10.
I suspect they did this to avoid possible compensations in case my phone will still have this problem in the future.
So , the question is, how can I prove that Android 10 update was downloaded and installed on my phone before I sent it in service? Does Google or Asus have some logs about that?
Thank you very much and, again , excuse the off topic.