Unless they gained access to your router, your wifi is fine. Even if they did, they'd then have to exploit a vulnerability in your phone or PC to get into that, and as long as you're up to date on your patches, they likely could not.
If you are concerned they got into your router, you can factory reset it and reconfigure it, make sure to use a good password and if it has the option to manage it from the WAN, disable that. Check to see if there are any firmware updates available for it (if the router is ISP provided, they probably manage the firmware updates and it should hopefully be up to date).
If you know that spare laptop hasn't been used since this all started, you could use that to download a fresh windows 10 image to a thumb drive and wipe your other PCs and use that to reinstall from scratch, which would get rid of anything they may have on them.
But I'm not convinced you actually have anything compromised. Sounds like you may have just been hassled by scammers, again if you did not install anything, click their links, let them take remote control of anything, etc, likely nothing happened. But if you want to be ultra safe and have piece of mind, and don't mind all the work, factory reset your router and reconfigure, factory reset your phones and reconfigure, wipe your PCs and reinstall from a fresh image downloaded directly from MS.
When you are reconfiguring stuff and downloading those images, do it from a PC that you did not use during all of this like that old laptop.
Scare tactics are one of the main ways they get you to do stuff. For example some malicious sites will pop up a window saying you are infected or your windows has been locked, then they ask you to call a number and provide your info, it is a fake number. All you do is close out the window, its just a website made to look like an error message. There are all kinds of things like that out there.