Synchrony Financial Credit Card Complaint

Synchrony Financial Credit card department,

Billing statement Washington

I was given a Lowes credit card at the store on -/-/2016 through Synchrony Bank and made a purchase the same day for $2100.00. The billing cycle was closed 4 days later and the due date listed was -/-/2016. I called the bank and they refused to change the due date. Is it legal to have the due date less than 30 days from the purchase date? Normally the billing cycle would be 30 days, not 4 days.