Hello, and sorry you're having problems. We are now connected on this website- which saves you money over having a Tech come to your home, and in many cases we can fix the problem you're having. In other cases, these things do require additional parts to fix. But I can help you with that as well.
Are you asking about replacing the LCD/LED screen on a 70" Vizio set here?
If so, is it because the screen is cracked or damaged?
If so, then unfortunately these screens are not available for purchase anywhere for these sets. Once the screen is cracked or damaged the TV is considered non-repairable since the screen would cost 80% of what the TV cost when new (when/if you can find them) and then it requires complete rebuilding of the TV to fix it.
The only possible fix for this is to search the SAME exact model number of your TV on Ebay, and purchase the set with a bad power board, or other issue then cannibalize it for it's screen.
If you can't find the same model, then you can also sell your TV with the bad screen to Shop Jimmy, and they will pay you for the parts. You can contact them here:
Other than that, I'm sorry for the bad news and wish there were a quick fix.
Feel free to reply back if you need more help, or want to reply back with more details. It does not cost you anything more to reply back once you've rated. Please do rate me positively (at least 3 STARS) and I will continue with you until this is sorted. The positive rating ensures I am credited for my work.