Neither. I'd probably call that business services or retailer/reseller.
There's also the salient difference that those takeaways are not being paid as contractors by Just Eat (if anything it's probably the other way around). If they were, Just Eat would be a takeaway. If Just Eat made a piece of software for sale that other companies could use to provide takeaway resale services, it would be a technology company.
There's also the salient difference that those takeaways are not being paid as contractors by Just Eat (if anything it's probably the other way around). If they were, Just Eat would be a takeaway. If Just Eat made a piece of software for sale that other companies could use to provide takeaway resale services, it would be a technology company.