Why am I being forced to use my mobile to contact John Lewis?

I offered my landline number and email address, but was told that I will need a mobile numberI have a John Lewis Partnership Mastercard, and pay the balance over the phone. The last time I did this, I was asked for my mobile phone number. I have an older, un-smart phone for emergencies, and it is nearly always switched off. I offered John Lewis my landline number and email address, but was told that, from next year, I would be unable to use my Mastercard for online purchases unless I provided a