Complaint around paint spill

I recently (3 December 2017) purchased a few items from the N1 City branch. We loaded the items in my boot and upon arriving home, found that the paint has spilled over my whole boot.

We immediately starting getting the paint back in to the can before it started hardening and tried to clean as much of the back seat, boot and the plastic spaces the paint had seeped into but unfortunately there is only so much one can do without proper tools.

After an hour of cleaning the mess, we went back to Builders and explained to the store manager what had transpired. He was able to refund us for the paint. It was acknowledged the paint was not properly sealed when the mixing process was completed.

The problem I'm still facing is that I need to get the car deep cleaned in order to get the paint out which has seeped into the spare wheel panel and all around the back seat covering. My only hope is that doesn't stick to the car permanently. I can acknowledge that mistakes happen and the service we received in store after coming back was greatly appreciated, I just don't want it be a mistake that I need to be liable for in terms of the cleaning. I'm sure this is justified.

Looking forward to feedback regarding this.