Unfair service from Takealot

I placed an order on 22/11. Chose delivery on Monday 26/11. I was away with poor reception over the weekend when they tried to deliver and I could not respond to their messages. The first delivery man was however able to contact me and I have a witness who heard me tell him to reschedule for Monday 26/11. My order was subsequently cancelled and they are telling me to repurchase at the new prices which are significantly higher than the promotion prices I paid. They are also keeping my money as credits against my will, as they are the ones who changed the original delivery date and now keep my money as credits.