public void Zoiper_OnAccountIncomingCall(Account account, Call call)
        {
            ActiveUsers[UserId].MakeCall(call);
            DialogResult result = MessageBox.Show("Accept call from: " + call.CalleeName, "Incomming call", MessageBoxButtons.YesNo);

            if (result == System.Windows.Forms.DialogResult.Yes)
            {
                var res = call.AcceptCall();
                if ((ResultCode.Ok == res.Code) && !ActiveUsers[UserId].ActiveCalls.Keys.Contains(call.CallHandle))
                {
                    ActiveUsers[UserId].ActiveCalls.Add(call.CallHandle, call);
                }
            }
            else
            {
                call.HangUp();
            }

            if (OnZoiperEvent != null)
            {
                OnZoiperEvent("AccountIncomingCall: " + call.CalleeName + " number: " + call.CalleeNumber);
            }
        }