Hi Ali. The fault is presumably not in your brakes but in the cruise control, as it is not disengaging when you apply the brakes so you are basically applying the brakes and accelerator at the same time.
In terms of how you proceed: if the car is under warranty, you should be able to chase the warranty provider to get the cruise control repaired. If not, then you should pay to get it fixed or alternatively get the cruise control permanently disengaged (pull the fuse, cut the wires, etc.).
I’m not sure why you’ve kept using the cruise control if it’s causing this problem – you say that you’ve had this problem five times now, yet you keep using the cruise control. Why?