I have a KPN SIM via YouPhone (number not mentioned here, for obvious reasons).
The phone is very light use, because I keep it primarily for contact regarding work contracts, but, for the past few weeks, it appears that all calls to the number have been going directly to voicemail, sometimes without even notification of the voicemail or the missed call.
This has already resulted in my missing out on one contract, which, I think you can understand, I am not entirely happy about.
Please arrange a non-public communication line, so I can tell you the SIM details.
BTW. It is not a problem with the handset. I have gone as far as factory-resetting the device.