Upload wordprocessing document to SharePoint list

I am trying to upload a document from my drive were I make a copy of my .docx file and then remove header and footer and then upload to my list.

I can open my document that I upload, but I get an error when opening it:

We are sorry we cant open lala.docs because we found a problem with its contents

                        using (SPWeb web = mysites.RootWeb)
                        {
                            using (mysites.OpenWeb())
                            {

                                SPList list = web.Lists["Arbetskopior för dokument"] as SPDocumentLibrary;
                                string file = fileName;


                                using (MemoryStream destination = new MemoryStream())
                                {
                                    //FileInfo f = new FileInfo(file);

                                    var exten = Path.GetExtension(file);
                                    if (file.Length > 0 && exten == ".docx")
                                    {


                                        using (Stream sourcefilecopy = File.OpenRead(file))
                                        {
                                            sourcefilecopy.CopyTo(destination);

                                            using (WordprocessingDocument doc = WordprocessingDocument.Open(destination, true))
                                            {

                                                var docPart = doc.MainDocumentPart;

                                                if (docPart.HeaderParts.Count() > 0 ||
                                                    docPart.FooterParts.Count() > 0)
                                                {
                                                    docPart.DeleteParts(docPart.HeaderParts);
                                                    docPart.DeleteParts(docPart.FooterParts);
                                                    Document document = docPart.Document;
                                                    var headers = document.Descendants<HeaderReference>().ToList();
                                                    foreach (var header in headers)
                                                    {
                                                        header.Remove();
                                                    }

                                                    var footers = document.Descendants<FooterReference>().ToList();
                                                    foreach (var footer in footers)
                                                    {
                                                        footer.Remove();
                                                    }
                                                    document.Save();

                                                    var byteArray = new byte[sourcefilecopy.Length];
                                                    string filename = System.IO.Path.GetFileName(file);
                                                    sourcefilecopy.Read(byteArray, 0, (int)sourcefilecopy.Length);
                                                    sourcefilecopy.Close();

                                                    bool addFilesNotExisting = true;
                                                    string fileUrl = list.RootFolder.Url + "/" + filename;


                                                    SPFile fileSp = list.RootFolder.Files.Add(fileUrl, byteArray, addFilesNotExisting);
                                                    SPListItem item = fileSp.Item;

                                                    item["Namn"] = fileSp.Name;


                                                        }

                                                    }
                                                    item.Update();