If you operate contact centers in different parts of the world make it easy for potential customers who may call a local office and find it closed to contact other offices if they want to. An example is when I called an airline to book a business trip from the UK to the US. It was 7pm on Sunday in the UK and I heard a message “Our offices are closed, call back between the hours of 7am – 6pm Monday to Friday or 10am-4pm Saturday and Sunday” That was it! – no web address mentioned for booking online, no other numbers available etc. I found their web address and contacted the US office, which was 5 hours behind and made my booking – most customers would probably just call another number.