Faulty Sat nav

[Brucie1988]

I’m pretty new to this forum but hoping to get a bit of advice regarding my satnav I got a 65 plate custom limited. The sat nav doesn’t work. The SD card has seen better days so I’ve been into ford and there are 2 types of SD card available for my van. There is a genuine Ford option and a TomTom option that is cheaper. Has anyone got the tomtom card?
Links of where to buy would also be helpful
Many thanks