Pathetic service and downgrade of bus without notice

I booked and paid a for a bog sky bus from midrand to durban paid the extra because of the comfort of the big sky, when the bus arrives only to find its a budget liner bus that is cramped dirty and smelly. My ticket says the big sky mainliner but the bus am on is a budget liner. I spoke to the consultant at the office who said he just puts the bus number they allocate. Contacted the call centre who only said they sorry nothing they can do i must email a complaint through and that they have the right to change to whichever bus they see fit even if we paid more. A budget liner bus is way cheaper than the original bus i booked and paid for. Theres so much of dirt in this bus and a coachroach like this is a pet farm. Disgusted by the treatment and responses from intercape.