bad service and quality

My husband bought me a ring in December 2018 as a surprise, the ring was too big for me and in January 2019 he took it back for resizing as i am staying in Mthatha and there is no NWJ but when it came back it was big again but i had to wear it, in March i noticed that 1 of stones has fallen then we took it back to Durban where he bought it and they said they will repair the ring but it is going to take 2 to 3 weeks, in mid May they called the and say the ring is back and my husband went to Durban last week and also collected it, i wore it then after a day i noticed that same stone is not there and the ring is changing colour my ring is rose gold, hey these people must take back their ring, it is not even 6 months of purchase and its giving me problems, please help