On November 30, a friend of Natalie’s asks her to teach a class at the neighborhood school.
Natalie agrees and teaches a group of 35 first-grade students how to make Santa Claus
Cookies.The next day, Natalie prepares an invoice for $250 and leaves it with the school principal.
The principal says that he will pass the invoice along to the head office, and it will be
Paid sometime in December'
DR account receivable 250$
CR teaching revenue 250"

Natalie receives a cellphone bill for $45. She uses her cellphone only for business. The bill is
For services provided during November and is due December 15
DR unearned service revenue 45$
CR service revenue 45$
But the balance of the unearned service revenue is 25$
What I have to do or is my transaction incorrect

The cellphone bill will be:
Debit an Expense account like Cellphone Expense or Telephone Expense Account and credit Accounts Payable for the amount

The cellphone bill will be:
Debit an Expense account like Cellphone Expense or Telephone Expense Account and credit Accounts Payable for the amount
Thanks a lot
Can I say telepone payable account

If you have a telephone payable account you can. You would need to look at the chart of accounts of the company to determine the names of the accounts or if this is homework the accounts should be listed in the problem.

As an added note, always think about whose side you're on. If Natalie receives a cell phone bill, how does that relate to revenue for her? She's not the cell phone company. She teaches cooking - teaching is her revenue. Services that she uses are expenses.