How to call post method for multiple parameters?

I would like to change the following api controller method from GET to POST request.  I have made the changes on the header however I am getting a the following error, whenever I call api/list?tag=89077&name=prest :

{"$id":"1","Message":"The requested resource does not support http method 'GET'."}

        [HttpPost]
        public HttpResponseMessage Post([FromBody] Query query)
        {
				IQueryable<data_qy> Data = null;

                if (!string.IsNullOrEmpty(query.name))
                {
                    var ids = query.name.Split(',');

                    var dataMatchingTags = db.data_qy.Where(c => ids.Any(id => c.Name.Contains(id)));

                    if (Data == null)
                        Data = dataMatchingTags;
                    else
                        Data = Data.Union(dataMatchingTags);
                }

                if (Data == null) // If no tags or name is being queried, apply filters to the whole set of products
                    Data = db.data_qy;

                if (query.endDate != null)
                {
                    Data = Data.Where(c => c.UploadDate <= query.endDate);
                }

                if (query.startDate != null)
                {
                    Data = Data.Where(c => c.UploadDate >= query.startDate);
                }

                Data = Data.OrderByDescending(c => c.UploadDate);

                var data = Data.ToList();

                if (!data.Any())
                {
                    var message = string.Format("No data found");
                    return Request.CreateErrorResponse(HttpStatusCode.NotFound, message);
                }

                return Request.CreateResponse(HttpStatusCode.OK, data);
            }

Do I need to change code in my global.aspx or somewhere else. Please advise. 

Many thanks.