Registering online with DWP. Friends Phone number?

Hia, I'm About to start managed migration from ESA to UC. Reading though the B&W guides, I need to register for an online account. It's mentioned about giving mobile or home phone number as well as email address. However, I do NOT use phones at all. Previously for benefit purposes I've always given my friend's phone number (who is also my unofficial carer). Can I continue to give her number when registering online with the DWP? If not then what should I do?

Thanks,
Ali.

Thank you. I'll note this on my Journal when I detail my complex needs and reasonable adjustments they need to make.

Sadly it appears I can't have write access to my journal until I've completed my to do list.

Ali.