Paypal credit payment mistake?

Description

So my PayPal credit payments have been on payment holiday by covid relief. Therefore my payment amounts have been £0.00, i received an email the other day about missing the payment. Initially i thought how is this possible to miss a payment of ZERO. So now I’ve been charged £12 as a late fee! How is this possible when its impossible to not meet that required £0.00 payment amount. Now my covid relief payment break has ended and my next months credit payment has jumped to over £150, I’m struggling to make by with just unemployment benefit as it is with the holiday and now I’m being stung with fees and a huge payment to meet.
What can i do?