Beware added extras

On recently (8 Dec) renting a car at Cape Town International Airport, everything was good, the agent doing her duty asked me 1 (one) main question, "do you want to add increased protection?" I understood this to be additional costs for waivers etc. On completing the whole transaction I was asked to sign the screen, this I did. The car was ready and we were on our way. Much later that day I received my documents (Rental Agreement) electronically and did not find it necessary to read these at that time. However on returning (10 Dec) the vehicle everything went smoothly and were returned home. Sometime during that day I received another document (Estimate of Rental Charges) on which an amount of R257.74 was added for Optional Services. I found out later that this was for Windscreen Damage Waiver, Tyres and Third Party. As far as I am concerned this fell under the question asked of me, regarding additional costs for added protection which I had already refused. On 3 occasions since then I have tried to get this rectified, the only person at fault is myself for signing the agreement, no one at Budget is too blame and everyone I spoke to just ignores it, the one lady said that the manager at Cape Town rejected my claim and then proceeded to try and resolve it, this was greeted with a positive reply, but till date noting happened and that lady doesn't exist. Another lady decided she wasn't going to deal with it and very professionally put the phone down on me, since then I have not been able to get hold of anyone at the branch. I have not phone the national number again as they just tell me to deal with the branch itself. This may be an insignificant amount of money, but it is none the less the principle. Thank You