Delayed response and delivery

They are the worst company to deal with, they never answer their phones, i have been on hold for over 10mins, an order of 3 items, has taken them 10 days to pick from the warehouse, they are slow and very insufficient. when my driver went to pick up the stock they asked if we can please give them proof of payment, we have asked them 3 times to take it off our credit, and yet they still didnt.... after complaining i was given an email address of who i should send my complaint to, if i am a paying client should they not contact me? this is not acceptable from a company that turns over millions