Noureen will discuss the issue with Nasir _____ phone.

Phone শব্দটির পূর্বে by বসে। কিন্তু the phone এর পূর্বে over/on বসে।
By phone: The company can be reached by phone on this number.
Over the phone: You can arrange a mortgage online, over the phone, or through a meeting.
On the phone: She has spent hours on the phone in recent weeks, talking to negotiators in a labour dispute.
Source: Cambridge Dictionary