ds is 15 both he and his sister (12) get a £10 top up every 2 months, they are on tesco so it gets tripled to £30 credit.
I topped them up on the 27th march and already ds has zero credit, in fact I suspect it has been more than a week. 
This is not the first time, I do not give in and give him extra credit (he does have pocket money as well and could do it himself) he never does though.
Do you think I should stop topping him up all together? After all he never replies to texts I send, what benefit am I getting out of it?