i will locate this and get back in touch cheers

I recently asked for 6 years worth of statements to be sent to me in a letter to the bank they sent me 3 years total charges £895 they said they'd refund half this charge, stupidy i excepted this, and i also signed a declaration at the bottom saying this would end anymore charges being refunded. however 2 months later i now have the final 3 years statements sent through £1650 charges in total!! can i claim this back, as the bank staff didn't do there job correctly the 1st time?? or am i bugered