Yes. When you activate SMS voting, you are asked to choose a phone number. This phone number will be connected to your account no matter how many polls you create. It will also remain if you renew your plan before expiration.
By default, the phone number will be removed from your account in 30 days after purchasing a one-time plan or signing up for a free account.
Theoretically, a phone number setup for your account can always stay available for you if you constantly use the service.
Note: This phone number is not your personal phone number and will be used for voting purposes only.