Ripped Prefolds,What did I do wrong?

[Sarah]

I'm new to cloth and don't have anyone to ask questions to forgive me if I'm full of them

I bought some used infant prefolds off Craigslist yesterday and when I bought them they looked fine. The mom I bought them from said they had never been washed in bleach so I went ahead with the sale

Today I washed 3 of them in hot water with a tiny bit of Purex and now all three of them have holes in the middle(where the dipe is thickest)

What did I do wrong? Can I still use them,until my fluffy mail starts to roll in?

Sarah