The diamond ring I bought at Lao Fengxiang was 13,000 at the time. Now Lao Fengxiang has 50 % off all the diamond ring. I want to add money to change one

The diamond ring I bought in Lao Fengxiang was 13,000 at the time. Now Lao Fengxiang has 50 % off all the diamond ring. I want to add money to change one, but the clerk says that the old is replaced with a new one.