FBA products showing longer delivery time than Amazon

Hi,
Has anyone experienced this with there own products?
I have CD’s that have been shipped into FBA and are showing as available but are displaying this message,
" Extended delivery time: Some low-priced Prime-eligible items, such as this, have an extended delivery window. Common reasons for an extended delivery window include items restricted to ground shipping and items that require extra time to prepare for shipment."
I have the buy box but delivery is showing as 4 days for prime members.

Amazon on the other hand are slightly more expensive but are next day delivery for Prime.

I wonder who all the customers are going to!!