You are using telephone for business usage, you can get ITC.
Give your GSTIN to your telephone company and they will show details in GSTR-1. Mobile is for business use only most of the time, though it is not possible to bifurcate but you can always prove that Mobile connection is for business use.
I will advice not to link residential telephone with GST as it is purely for personal purpose.
You can change the telephone to your name if telephone company is not allowing to link GST with owner name.