SIL/MIL need help!

I'm a FTM and have never had a great relationship with my sister-in-law or my MIL... Since getting pregnant all they do is shop for my baby... Great right? Well yes it would be except they only ever buy clothes which we did need.. However now I have a dresser full of clothes and a closet full of clothes... I have asked them both to kindly stop buying since we have plenty and are out of space... Not to mention the fact I haven't even had my shower yet... But boxes and boxes of clothes keep showing up at my house... My husband won't say anything to them... I know I should be great full and I was at first but now I have no space for anything else. How can I get them to stop?