The simple fact is that you will be charged a late fee if your payment is late, regardless of how late it is; even a single day late
counts as a late payment, so be sure to pay on time or, perhaps, even early.
Not exact matches
With that being said, making a
late payment is most likely going to negatively affect your credit score, so that
counts as messing it up.
If you make multiple partial
payments that total at least your monthly
payment amount, and you make those
payments no
later than 15 days after the scheduled
payment due date for that month's
payment, the series of partial
payments will
count as a one qualifying
payment for PSLF.
For instance, once a
payment is 30 days
late, most companies will
count it
as late, even if you have a dispute in the works.
If you do have an emergency e.g. a death of a close relative, do call your mortgage company and they may just not
count the
payment as late and report it!