Virgin Mobile is a prepaid mobile phone service. They advertise a specific length of service per top-up of the account. The plan I am on requires a $20 top-up every 90 days and they also offer a "Service Preserver" plan which requires a $90 top-up for a year - of course if one exceeds the # of minutes covered by the $ purchase additional top-up would be necessary during the period. They frequiently offer specials of $15 for 90 days or $60 for teh "Service Preserver". Unused minutes roll over from period to period so long as the service is maintained. This service is designed for people who seldom use cell phones, usually only for emergencies, and many never use all the air time they pay for so the calendar time limit is usually the governing factor.
Recently I received an email offer for a $60 "Service Preserver" top-up to main my service for the next year - the price is normally $90. I called Virgin Mobile and confirmed the offer with one of their customer service reps, and only topped-up after being assured that I would actually be given a full year. After topping-up I noticed that I had only been given 90 days. In calls to their customer service they denied ever making the "Service Preserver" offer, refused to allow me to furnish proof of the offer, refused to honor the offer and refused to refund my money.
Also, a standard practice with them is to cheat the customer on length of service by trying to get the customer to top-up early. Customers get an email at least one month before their period ends urging them to top-up to avoid losing service if their period ends without topping-up. If the customer tops-up early, the 90 day (or annual) period begins from the date of the top-up rather tham being added on to the the present period. For instance, if your service is good through Sept. 30 and you top-up on August 31, your next required top-up date would be around November 30 so you really only bought 60 days rather than 90 days.