You would have to contact Paypal for any issues related to making changes to your 1099-K.
Please note that the 1099-K is for your information purposes only (unlike a 1099-MISC) so if the amount that is actually your taxable income from Paypal is less than what is being reported on your 1099-K, just report the correct amount when you are reporting income on Schedule C (self-employment income).
Just make sure to keep a copy of your 1099-K with your records.
