Storefront API not returning results as expected

[hwaqar44]

I’m building an app using Shopify Storefront api. So far I’m able to fetch products, collections. But when I try to filter the products in a collection it is not returning results as expected. Here is what i’m trying in postman

{
  collection(id:"Z2lkOi8vc2hvcGlmeS9Db2xsZWN // collection id"){
    products(first:10, filters:[{productVendor:"ADDIDAS"}]){
      edges{
        node{
            id
            title
            description
            productType
            vendor
        }
      }
    }
  }
}

But i’m getting results that have vendor of NIKE and other types. Do i need to change something? But when i try filter using price it works fine but when i try filtering using productType it is giving me not expected results. Am i doing something wrong? Please help here