public async Task CreateInvoiceAsync(RunMyAccountsInvoice i)
        {
            Regex rgx = new Regex("[^a-zA-Z0-9_\\.\\-\\\\]");

            i.ordnumber = rgx.Replace(i.ordnumber, "");
            var request = new RestRequest("{tenant}/invoices", Method.Post);

            request.RequestFormat = DataFormat.Json;
            // request.JsonSerializer = serializer;
            request.AddBody(i);
            var response = await client.ExecuteAsync(request);

            if (response.ErrorException != null)
            {
                throw new Exception("Failed to add RMA Invoice: " + response.ErrorMessage);
            }
            if (response.Content.Contains("{ \"error\": \""))
            {
                throw new Exception("Failed to add RMA Invoice: " + response.Content);
            }
        }
        public void CreateInvoice(RunMyAccountsInvoice i)
        {
            var task = CreateInvoiceAsync(i);

            task.Wait();
        }