unfair

I have taken a contact over from my brother the contract is ending april, so he asked them to change the sim card to pay as you go as they explain to him that I need to use all the airtime by the 14th otherwise I will loose al that airtime. what I think it is pathetic as I paid for the airtime know I need to phone all that airtime out I say BULL DUST. they are quick enough to sell a contract to you, know that he has upgraded to a new phone and sim card and asked them to put my sim card as pay as you go and know I must loose al that airtime. pathetic beyond. then they need to pay all that money back!!!