Delivery offer misrepresentation

I went online to purchase a bed and mattress protectors because of the offer of free delivery for online purchases. There was no indication that there are T&Cs involved and even went on the FAQs and also on my invoice (with my address, delivery was R0.00).

I paid for my purchase and next thing I am required to pay R550 for delivery, when I called online service I was transferred to at least 5 people before I talked to somebody because they all couldn't assist or it's not there department.

I spoke to Betty who said she'll have to ask delivery and when she called me back she said that Dispatching said that I am out of delivery zone which is +100km (note: 50km is the return trip) and have to pay.

There's not even an asterisk on the free delivery sticker, indicating that there are Ts and Cs involved.