I have an FNB home loan with a Flexi facility that allows me to have access to any additional funds I have paid into my bond. I was recently notified by FNB that the terms of use for the flexi facility have changed and the new terms are much more restrictive and reduce the benefit of this facility. My question is can FNB do this? Seems like a bit of a unilateral decision.

Details of the Flexi facility changes:
https://www.fnb.co.za/home-loans/flexi-facility.html - under the Flexi FAQ's, point 15