You DO NOT call them to pause or suspend the account. That will result in a monthly $10 "Maintenance Fee" to keep the account active. What you do is call them and tell them to CANCEL or DISCONNECT your service. The wording you use is critical to getting a credit for the unused portion of your prepaid month. Then you will receive a remaining balance credit on your account against the charges when you want to restart your service or your can ask for a refund of your credit balance. I have done it this way for the past 10 years and never paid for more than the partial month I used.
I have never paid any fees to put the account on hold, regardless of what word I use.