Far be it for me to suggest how to run a well established business, but speaking as a customer, timely processing of online orders, has a lot to do with WHICH online retailer i will do repeat business with.
For example: retailer A has a part i need, their website shows it being in stock, but does not even LOOK at my order for 10 days, then ships ground, making the total transaction time over 15 days. Now retailer B has the same part, same price, but ships the part in a more reasonable time, resulting in the CUSTOMER getting their goods , the vast majority of time, package in hand in under a week.
Doesnt take a brain surgeon to figure out who gets the repeat business..
Now for suggestions:
When an email order is recd, have an autoreply sent stating a forseeable delay in order processing, with the option to cancel the order , if the customer wishes. This option is free, takes no manpower, and is extremely easy to set up. If you needed assistance in setting this up, i would be happy to assist.
Second and most importantly, treat people who call ( your bread and butter) with respect.. Someone calling asking if there was an issue with their CC#, should not be answered with" we didnt even look at your order yet... Prolly sometime next week...", even after the caller explained it has been well over a week..
I hope this constructive criticism helps..