i sat down and started to play this morning, but 53 keys, to me, sound odd. like if you were to put down the middle pedal down and all the keys get softer and harder to press. i get the feeling that those 53 keys are as the middle pedal were down. sometimes when i press a key it doesnt press as well. From about C3 to A7 ( some keys are okay ) i have trouble playing my music . should i call for a refund or is there a way to fix this problem? :/