lift staff rude and don't want me to take a brand new car part which is not hazardous as check in luggage

Flew from Durban to Johannesburg yesterday with lift,purchased a brand new car clutch kit which was sealed,lift refused to let me take it as carry on stating that it is not allowed yet it is not listed on items not allowed,the counter staff ****h was very rude and spoke to me anyhow and called her manager who also was siding with her after me stating to the manager that they can open the box which was small to confirm if the part was new and the receipt was also in the box,he refused and stated that it was not allowed even after I informed him that the items was not classified as hazardous or flamable or dangerous,he did not even take not or apologise regarding the counter staff, ****h's rude behaviour and when I told him I was going to post a negative review he stated go for it.Will never use this useless airline again with rude staff,I was then told they would keep this part till the following day 14:00 where if it is not collected will be destroyed.