Customer Support for a Villa Rental Agency in Spain / Virtual Assistant/ Etc.

Hi,
I am looking for a virtual assitant with good Spanish and English skills to help with customer messages, requests, inquiries and incidences in the European evening hours on some weekdays (e.g. Wednesday, Thursday, Friday from 12h - 16h GMT-4) and on weekends. I cannot exactly say the hours required on weekends as it will depend on the amount of customers inquiries, calls and messages entering. Would you offer an "on demand" service on Saturdays and Sundays as it would be only to be available in case customers have incidences, questions or if there are booking requests.