So apparently red wine and red wine vinegar for cooking are different and I didn’t know this. So for my beef stew I a cup of red wine vinegar instead of red wine (which I know nothing about wines either way) so now my vegetables taste terribly of vinegar. Is this fixable or should i toss it out? Please help 
It is not possible to remove the vinegar taste. You can try augmenting it by sweetening the stew (using something more interesting than white sugar, as ChrisH points out in his answer) and adding warming spices, to move it in a sauerbraten direction. If this doesn’t appeal, throw it out. 