Hello,
IELTS will conduct all 4 module same date, very rare next day. Self experience.
If you have more doubts, you must call IDP or British Council the location where you made payments, they are the best person to clarify. You paid money, now focus on your IELTS exam. Rest all headache is IELTS, now.
Additionally, Abhi time to start focusing your passage and English skills, here also.