Send it back I'd say.
I would be happy with just lip sync being wrong. I have had this TV for just gone 8 months and six weeks or so ago, it started resetting itself randomly. Whatever I was watching (Digital TV - Standard and HD; Internet TV; iPlayer; DVD/BluRay), whatever input cable (HDMI, Scart), whatever was plugged into it (Aerial only and various combinations of DVD, Internet). I have upgraded firmware and run through resetting the TV (inc. powering it down, waiting an hour and then starting it again) but it is still the same.
Samsung support in the UK is as good as useless for this TV. If you have proof of purchase, then take it back, especially if you have a 'no questions asked' retailer. This is for many reasons, but for me, under warranty Samsung will collect it when the TV is smaller than 32in, but an authorised Samsung repair centre will only collect it if is is 37in or greater. So this size of TV means it requires you to actually take it to the authorised repair centre yourself. Also, from other forums/sites on the web, when they repair it, the problems disappear for a week or two and then reappear again.
I have not got time in my week to take a TV to an authorised Samsung repair centre (they are not everywhere), only for it to get repaired into a state where the issue may return. So when I do get time to take this TV anywhere, it is going go to straight back to the store for a refund, so I can then forget about having to find another rare bit of spare time to collect the TV again. The stores are more abundant than the Samsung repair centres (so I don't have to drive it as far) and the issue is dealt with then. Given I get paid by the hour and it will take a half a day all in to sort it (wrap it, box it, drive it, hand it over and similarly on collection) it approaches two thirds of the cost of the TV that I lose in income. They refer to that as 'an inconvenience'. So all in all, I think this is a no brainer for me.
I have 3 out of 3 Samsung products that are failing me at the moment, so I have written them off as a bad job, longevity wise. I work in tech and if people ask for my opinion on Samsung, that's what I will tell them. It's the result of a real world test after all.