Rim repair failure

My husband took two rims to be repaired at Tiger Wheel & Tyre Strubens Valley. To our surprise, we received an email notifying us that the one rim would be s****ped because they were unable to repair. This is after they did some welding work on the rim. The explanation given was that because of previous work done on the rim, they are unable to stop a leak and a new rim would have to be purchased. Firstly when the two rims were taken in, they did not say that they wouldn’t be able to repair it if work was already done previously. Secondly they mention that they have done some welding on the rim and could not stop it from leaking air. How are you not able to stop it leaking but when the rim was sent in, it did not have a leak. Lastly they say we need to purchase a new one, at whose cost because certainly they cannot expect it from us seeing that they failed and in their failure, we now sit with a leaking rim. We responded to their email requesting answers and received no response back. We have also not received our rims back and they have been sitting with them for weeks now. We are frustrated and quite frankly upset about this situation and to leave us with no answers is unprofessional and unbecoming for an establishment like this. Very disappointed in them. Wheel Collision was also involved in this incident