Poor workmanship for rim repair at Mintys Tyres - Bedforview

I took my mag rim for repairs to Mintys inBedfordview as it had a slight crack. Due to the poor roads to and from work, I had to have this repaired a few times. on this occasion I was told by the agent Abie that it would be beneficial in the long run to have the rim rebuilt rather than have it welded. this was a bit more expensive, but I accepted as he told me that it would definitely last much longer. however after about two months, I had a same issue again. when I took it to them, I was told that they will need to send it back to their service provider to have a view and get back to me. during the day I was called by Abie stating that I need to pay R1000 to have this repaired. this agitated me as I believe that it was poor workmanship as a rebuilt rim should not crack so quickly. they argued with me and was not hearing any of my argument. I find this extremely unacceptable as I paid a lot of money to have my rim rebuilt to prevent another issues like this. I was then told that even if the rim was rebuilt it will still crack. this I find amazing, as none of my other rims got cracked, but just this one. I was expecting a little more from the agents in terms of customer support ant etiquette, which I got none. All I want is either my rim gets fixed at their cost or refund me for the previous cost which was shoddy workmanship. Thank you