No way to contact Builder's Warehouse, Rivonia

Had two orders, only discovered there was a delivery charge once the goods were delivered and the invoice was sent to me. Also the invoice was very confusing, the vat and delivery were shown as one item and when working out the vat, the delivery didnt make sense. Several items that were charged for and marked "pending" have still not arrived after several weeks, and no notification has been sent to me. The frustrating thing is that I cannot get hold of them. I have called their number several times without success, been sent to various different departments and landing back at the switchboard! Once I waited 45 minutes for someone to speak to and eventually rang off. I have emailed through their website and emailed their given address. HELP!!!! What am I supposed to do in the time of COVID, where I am compromised and cant go out?