public async Task <ActionResult> AcceptAppointmentRequestAsync(string appointmentId)
        {
            var userId = _userManager.GetUserId(HttpContext.User);

            TempData["AcceptAppointmentMessage"] = "You have accepted the appointment!";
            try
            {
                await _sellerService.AcceptAppointmentRequestAsync(userId, appointmentId);
            }
            catch (Exception ex)
            {
                TempData["AcceptAppointmentMessage"] = ex.Message;
            }

            return(View("AcceptAppointmentResult"));
        }