Used laptop sold as new. Laptop collected no word from PC Link since

I bought a laptop online and the service was great when I was buying. I chose to collect from their Florida Glen branch. When I opened the box at home to setup laptop I found it had a scratch. I emailed them and the one manager asked for a serial number but never responded after that. The other whom I had been engaging since payment went through responded saying laptop was second hand hence it had a scratch and was on promotion when I bought. I responded to both saying nowhere did it mention that its second hand and that I want a new one. They didn't respond instead they sent a driver to collect the old one. I have followed up to establish whether they are refunding me or giving me a new laptop. What is my remedy? I urgently need this laptop for school.

T