Welcome Jen
If I were you, I'd be calling the "tradesmen" back in to fix the problem, or insist on a refund (if it's the same tradies). They've only applied bandaids by adding sand & relaying.
As Isobel said, you need to identify what is causing the problem, I suspect it could be roots from a nearby tree, & they need to be dealt with, before relaying the pavers.
I confess that the pavers that I laid over 30 years ago here at home, were only set in building sand, but it was/is a light traffic area. Incidentally, our pavers are lifting now because of our root issue, but it's not serious enough that I've had to deal with it.
I'm physically pathetic compared to those earlier days, but if I had to do it tomorrow, I'd lift the pavers with a large screwdriver at the raised areas, use the same screwdriver to loosen the soil around the roots, & remove the sand around the roots by hand. I'd then assess whether I could cut out a section at a time of the roots with loppers, or a plumber's wire saw (used for cutting PVC) to make the cuts.
Once the offending roots are removed, it's only a matter of filling, & tamping the void. The sand won't be enough on its own, but don't rush off for more sand, just add some soil from your property, it'll do fine.
Lay the pavers onto your flat bed of sand, & let them settle over time without tamping. If an area subsides, lift those pavers, repack with some sand/soil & plop the pavers back on top.
It may take time to reach perfection, but it won't be back breaking work.
Please, feel free to ignore this post if it's not physically possible for you to do what I suggest.
