A lot of people are unaware of any grace period for goods or services they purchase. The vast majority of people figure they are stuck with the 2 year commitment, and while they detest the situation, you would be surprised at how many people just don't want to deal with it at that point (too busy, tired, intimidated, confused, overwhelmed, life a mess, don't like admitting they didn't understand what they got into, etc.) and just give up and live with it until the commitment ends down the road.
Seriously, this is how it works and all the companies know it. One would think that people traveling to Vegas and playing in the casinos would learn about gambling and the odds and how to play the games well enough and avoid house bets and practice money management, discipline, etc. before they put down any money on the tables, but they don't. People either stay too long or not long enough and make a lot of house bets along the way or poor decisions at the tables (the object of Blackjack isn't for the player draw cards with a point value as close to 21; it's to let the house go over 21 while the player stays at the lowest point value possible). But That's how it works, and that is how the casinos really make money. Same with grace periods and rebates--the forms, etc.