echeck chargebacks?

[bglkk]

Hi:

 

We've just had a pending echeck clear (via Paypal) for a large order (US $8,000+). Even though it has cleared, Sales has decided to refund the payment and hold shipment until they pay by wire transfer instead (there are some suspicious signs about the order). Just curious--is it possible to do a chargeback on a cleared echeck? Not familiar with the process, and trying to educate myself...