Manually changing the EOT?

I am currently offering a 7-day trial offer of the membership, however, due to some technical issues, some members are unable to access the site for a couple of days during their trial. Since it is not the user’s fault, I want to add a day or two to their trial, however, I can’t seem to be able to manually change the OET from July 11th to July 12th, because once I manually edit the date and save, it is changed from 12th to the 18th, and whatever I try, it will either accept the 11th, or switch to the 18th.

Is that an impossibility or am I doing something wrong?

I assume that this is because of the 7-day trial period. Have you considered temporarily extending the grace period?

Maybe that would do. Where do i change that?

In PayPal Options -> Automatic EOT Behavior -> EOT Grace Time