If anyone else gets one of these "bills", it is not a bill, it is a receipt for payment.
The phrase - "Entrega a cuenta por la compra de los inmuebles" which appears on the page
translates to
"Installment of account for the purchase of real estate" & it relates to the initial reservation deposit of 6000 Euros less credit card charges.
I knew that Spanish dictionary would come in handy!!!
Noreen.