band member instrument problem

I have bought every band member every instrument in the whole game, in fact I have every single thing you can buy in the whole game, but some of my band members are still complaining they don’t have a good instrument! is there something wrong with the game or something? I am unable to buy anything because everything is already bought!!! how do I stop my band members from complaining they don’t have a good instrument when they have everything buyable in the whole game?