I changed my payment date from the 23rd of the month to the 16th of the month but they also changed my statement date to the 16th as well. Is the payment and statement date linked?
Yes. The statement date is always a couple of days before the payment date.
Bulb take payment in advance, so your statement is deducted from your account, shortly followed by the payment for next month going in. The balance on your account should always be greater than or equal to one monthly payment.