Membership Plugin Not Auto-Rebilling

Settings:

Mode: Serial
Period: 30 days
Price: $9.99

Since "Serial" means "user remains at this level for a set period of time and is then renewed at that level", I assumed this meant they were automatically rebilled. i also assumed that the "Single Payments Gateway" (what I am using) did not infer that it can only accept payment 1 time.

Am I wrong on either of the 2 above assumptions?

Thanks.