Did you consistently have good sales previously? You mentioned the most sales are made when a new collection comes in maybe the new collection this time around was not to peoples tastes hence the decrease in sales?
Another factor is do you sell clothing for all seasons? Not to point out the obvious but if you only sell clothing for spring/summer sales will start to decline.
Also, delivery times can be a major factor in whether or not customers return, is your delivery on par with competitors? If your product is identical to competitors and you charge $2 less but their delivery times are days quicker customers will likely still use them as people tend to be very impatient.
Another factor is do you sell clothing for all seasons? Not to point out the obvious but if you only sell clothing for spring/summer sales will start to decline.
Also, delivery times can be a major factor in whether or not customers return, is your delivery on par with competitors? If your product is identical to competitors and you charge $2 less but their delivery times are days quicker customers will likely still use them as people tend to be very impatient.