If that is a company cell phone - the cost is deducted on the company's tax return.
However - if the cell phone is used for both - personal and business purposes - you would need to determine the percentage of business use.
The portion of personal use is reported as your wages.
We still need to treat you as a physical person and S-corporation - as separate entities.
S-corporation is your employer - and pays wages for your services - so when your employer provides you a cell phone for personal use - that value is classified as fringe benefit - a form of compensation.
Just an illustration example...
Assuming total annual cost of the cell phone service is $1200.
You determined that 80% of calls are business related and 20% are personal.
So the personal use is $1200 * 20% = $240 and business use is $960.
Thus - S-corporation will deduct business use of cell phone $960
and will deduct $240 fringe benefits as wages
wages will be reported to you on W2 form and will be taxable on your personal tax return.