why capacitor accumulate less charge in higher frequency
No, Capacitor will store more charge at higher frequencies since, its Capacitive
Reactance is low for higher frequencies than the lower one. So the capacitor gets charged faster and outputs more current in the circuit when it discharges.

At lower frequencies, capacitive Reactance is high so that current entering into the capacitor is low. This is why capacitor takes more time to charge and outputs less current when it discharges. 

To say simply, frequency is inversely proportional to reactance and directly proportional to current.