This issue affects customers using the O2 network only
If this is the first time you have used call forwarding on your mobile, it is likely that for the first 24 hours following activation any rejected/declined callers will hear a message informing them their call is being diverted.
This recorded message is played by O2 as a security measure, and will automatically cease after approx 24 hours.
Unfortunately this means that if the caller hangs up during the recorded message, our service will not be able to unmask the call - the caller needs to therefore be on the line for around 6 seconds for us to perform the unmasking.
After approx 24 hours O2 will remove the recorded message, and any rejected/declined callers will simply hear standard UK ring tone and be unmasked within our usual 2 second timescale.