We have tried grounding them, taking all their privledges away, we have tried reward systems and nothing works. They have started lying about getting the work done and turned in when they know we will see that it wasn't done. They have been grounded almost all school year and they just don't seem to care. Any suggestions?
Is it getting done and not turned in, or is it not being done and not turned in?
I think this is a fairly normal thing for kids this age to do between the ages of 12 and 14, and if the habit isn't stopped it can turn into a real problem in high school.
To begin remedying the problem (because it's going to be a process), you need to find out why your kids have stopped doing their work. There are a lot of reasons this could have happened:
These are just a few reasons I can think of off the top of my head, there might be others or it might be a combination of things. Either way, a good heart-to-heart conversation is in order. My experience has been that teenagers and pre-teens can sniff out disingenuous people faster than a drug-sniffing dog can locate a bag of heroine. Be prepared to calmly discuss with them exactly why you're concerned about their refusal to do their work. See if you can get to the bottom of the refusal. At their age, you should not have to sit with them while they do their homework, but it might be the only option left to you. Sometimes when kids rebel like this, what they're really saying is, "I need my mom and dad's attention". Even though they're older and more self-reliant at this age, it's an incredibly difficult age--one which probably requires more parental support and guidance than we realize.
Talk to their teachers and see if they can make the work up--or even just some of the work. Commit to sitting down with them and making sure the work gets done--even if it takes all weekend. Your children will know that you think this is important. They won't like it. Resist the temptation to say, "If you'd done the work the first time it was assigned, you wouldn't have to be doing it now". Deep down, they know it and pointing it out will only build a bigger barrier between you.
If NONE of that works, you might just have to let them learn a tough lesson their own. It will be painful for all of you, but for some kids the only way they will ever learn is to fail and have to dig themselves out on their own.