Found a solution. Turns out instead of getting it via Umbraco.Media (which gets a content object) you have to use the media service and use a get call call there.

//DELETE OLD FILE
                string OldIMGId = memb.MemberProperties.Find(x => x.Alias == "profilePic").Value.ToString();

                ///todo:Get delete media working or leave it alone? Maybe have a function that runs once every now and then and cleans up the db.
                if (OldIMGId != null && OldIMGId != "")
                {
                    var temp = _mediaService.GetById(int.Parse(OldIMGId));
                    if(temp!=null)
                        _mediaService.Delete(temp);
                }