I feel so sad but luckily to know that you are very strong and high EQ.
I think from another side, actually might be your 99 just want to take her "little gold" to help her daughters. But after going into your "safe box", she thinks might be this time can let you to help her lor..... you have so many gold........ then she takes it lor!
So, think about from this side, she might be intended to cheat you and your husband lor!
Anyway, you are right, as the gold can't back, think how to solve the problem is better.