Ok, so we changed broadband provider from plusnet to talk talk, that's when the air printer packed up, would no longer pick up and wouldn't stay on wifi.
Every time we tried to print a message would come up saying printer and device must be connected to same network.
Just as we thought it was KNACKERED and we'd have to buy a new printer, dh thinks lets just try using the old ( plusnet) router.
Well it's worked, the printer now works fine, we have full broadband, BUT my worry is this.. Talk talk are our broadband provider but we're using a plusnet router, so can anyone tell me if this is ok?
Dh said talk talk are providing the line, it doesn't matter what router you use, but I'm worrying plusnet will send us a bill, and I'm just generally very confused 
Is he right? That's the router isn't relevent?
All and any help or advice very gratefully received ??