Pissed off fake jewelry

I've made 5 jewelry purchases from the womanhood at Poshmark and each one I specifically asked is it 100 percent sterling silver 925 or plated,???? I was told sterling,925 4 of the 5 all turned colors the silver left an ugly reddish metal poshmark support will not refund you after 7 days well it takes longer than 7 days for things to turn colors if you don't wear them everyday they want you to repost them and resell them you can't do that that's lying to your customers that's disgusting and immoral I want my money back for these purchases and I have been banned from speaking to the people who sold them to me I can't send messages I can't speak to them so this is how I'm going about my final step everyone beware on jewelry items