Huawei
Enable or Disable Call Forwarding auf Huawei
On most Huawei phones, call forwarding is preconfigured by your mobile carrier rather than by you. That is why calls sometimes get redirected to voicemail or another number without you ever setting anything up yourself.
The three separate conditions - busy line, no answer and device unreachable - each have their own on/off switch and their own destination number. Checking and adjusting them individually is the only way to stop unwanted diversions or to set up forwarding the way you actually want it.
To reach the controls, go to Open the Phone app ➔ Open the menu ➔ Open the settings ➔ Tap on Call forwarding. From there, pick When busy, When unanswered or When unreachable and confirm any change with Change.
If forwarding still stays active after you disabled it here, the setting may be locked by your carrier on their network side, and a call to their support line is the faster fix. Keep in mind that forwarded calls, especially international ones, can be billed at different rates than a regular call, so check your tariff before turning on a permanent diversion.