pdl default & score

If its sold to a third party collector, it can have an effect. But you can dispute and remove them also

If you default on the payday loans, then the lender/creditor may report the delinquency to the major three credit bureaus and as a result it will have a negative impact on your credit score.
Moreover, unless the previous loans are paid off, you may not be granted pdls in the future.

Unless of course it was an unlicensed/illegal lender to begin with, that would be a whole different ball game.