Sky mobile call divert cancel

[Nowyouseeme]

Hi, 

I have a iPhone 13 and for some reason if I don't answer my calls it diverts to my other sky mobile phone.

in IOS setting call forwarding is turn off - it's driving me insane as all I want is if I don't answer my phone is for it to go to my voicemail. 

please can anyone help before I throw this phone in a river 

[caesarome]

Does this help which is taken from here:

https://www.sky.com/help/articles/making-a-call

Divert all calls:

1. Dial *2 1* then the number you want your calls diverted to.
2. Press # and you'll hear a confirmation message, followed by a high-pitched tone.

To stop diverting all calls, dial #2 1 # on your phone. Or *#2 1 # to check what number you've set calls to divert.

Divert unanswered calls

1. Dial *6 1* then the number you want your unanswered calls diverted to.
2. Press # and you'll hear a confirmation message, followed by a high-pitched tone.

To stop diverting all calls, dial #6 1 # on your phone. Or *#6 1 # to check what number you've set calls to divert.

Divert engaged calls:

1. Dial *6 7* then the number you want your calls diverted to.
2. Press #. You'll hear a confirmation message, followed by a high-pitched tone.

To stop diverting unanswered calls, dial #6 7 # on your phone. Or *#6 7 # to check what number you've set calls to divert.