Internet mail

Last Saturday I was sent an e-mail supposedly from UPS the delivery company telling me my parcel was going to be delivered in the next five working days and to see my parcel tracking number I had to open the attachment. Warning bells began to ring. I was not expecting any parcel. So I have not opened the attachment. I have looked up UPS on the web but, the number in England is an 0845 number and in Spain a 902 number, both of them I think are expensive to call to verify the authenticity of this e-mail. Does anyone out there deal with UPS? as I have to open an account with them before I can send them an e-mail.