Need help dealing with overbearing sister in law and clingy mother in law

SIL likes to dictate our lives and it’s getting too overwhelming. She comes to our place and tells us what we need to buy or own. She also forced us to use her old baby mattresses (last used was 5 yrs ago) when I told her I’m not comfortable with it. She got upset with me when I didn’t wanna accept all her kids’ old clothes as some had holes and some were moldy. I did keep those that looked wearable. And the baby chair looked unstable and had the moldy plastic smell. When I had baby blues (mainly because of her overbearing behaviour and my MIL’s constant visiting and not allowing me and baby to have proper rest), she told my husband she didn’t have it so she feels I shouldn’t have it either. I finally broke down one day and cried loudly, which my MIL accidentally overheard, and now she and my MIL feels offended by me. It’s like I don’t even have the right to be upset. While my husband have told them to back off from me, they’re still telling and dictating what my husband needs to do. Now they want our new maid to go clean my parent in law’s house also, which I feel is not right. And insist we go stay over at my parent in laws’ place regularly (we are living with my parents temporarily until our new place comes), which I find unnecessary and logistically too much. They have been trying to convince my husband to continue this living arrangement and rent out our new house instead. These are just a few examples of the things they do, and I honestly cannot take it anymore. No matter what my husband tell them, they just won’t back off from him. Even though they don’t directly approach me now, they still approach my husband to enforce their ideas on him, which then affects our new family as a whole, and I am really very very of their nonsense. My husband is also at his wits end because they would threaten him that he would break down the relationship at home and they would stop showing concern or giving us anything else if we keep rejecting their ideas and ‘help’. Even basic thing like naming of our son, my sis in law also threatened my husband and said if he insist on naming our own son, it will break apart the family. In the end we had to give in and let my FIL name him. Please help give me suggestions on how my husband and I can deal with my SIL. #firsttimemom #advicepls