The contamination thing is strictly her own narrative right now. She's drummed up her own experts that are saying she's clean and it was a contaminated supplement and that she's provided evidence proving this. None of that evidence has been judged by WADA or another body as valid at this point. That's what will be determined in her appeal.
Both of her samples were tested, both of them tested positive for the the banned drug.
We've seen people get many of these bans reduced based on accident and mistake or something that means it was unintentional. In those cases, almost always, they have been something similar to a steroid found commonly in other food or substances. So as ridiculous as some of the excuses that players have come up with, they are talking about something a bit more like a common, like for instance, the ones that have popped up in many South American athletes cases related to meat contamination.
Halep's case is different because it's a different class of drug, one that is uncommon in other products and uses. Going by what those in the cycling community had to say, accidentally taking it in some way or another is very rare. So Halep is going to need some blockbuster evidence to prove her case. Going off of just a guess, if she's claiming this is evidence that would clear her, I would hope that at a minimum, the supplement she's saying was contaminated was made by a manufacturer who makes the banned drug along with the supplement in the same facility. That would be the starting point for me, if she can't prove at least that, I'm thinking full ban because the contamination will make little sense if at least that isn't true.