Unable to validate added row tableview textField in swift

For one category i have added extra row in tableview, but i am unable to validate its textfield text value.

this code:

  var finalSearchValue : String = ""
  var finalSearchValueAmnt : String = ""
  var cell : BillerTableViewCell?

here i have added extra row Amount, but i am unable to validate that textfield

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

if indexPath.section == 0 {

    cell = tableView.dequeueReusableCell(withIdentifier: "textfieldCell", for: indexPath) as? BillerTableViewCell
    cell?.searchTextfield.delegate = self

    if self.rowCount! - 1 >= indexPath.row
    {
        if let customerDetail = selectedBiller?.bcustomerparms[indexPath.row] {

            alertParam = customerDetail.paramName
            cell?.searchTextfield.text = alertParam
            if var priceOfProduct: String = customerDetail.minLength {
                alertMinL = Int(priceOfProduct)
            }
            if var priceOfProduct: String = customerDetail.maxLength {
                alertMaxL = Int(priceOfProduct)
            }
            cell?.searchTextfield.addTarget(self, action: #selector(searchPhoneEditingChanged(textField:)), for: .editingChanged)
        }
        else{
            print("no tf")
            cell?.searchTextfield.text = "missing"
        }
    }
    else{
        cell?.searchTextfield.text = "Amount"
        cell?.searchTextfield.addTarget(self, action: #selector(searchAmountEditingChanged(textField:)), for: .editingChanged)

    }
}
return cell!
}

@objc func searchPhoneEditingChanged(textField: UITextField) {
finalSearchValue = textField.text!
self.textCount = self.finalSearchValue.count
}

@objc func searchAmountEditingChanged(textField: UITextField) {
finalSearchValueAmnt = textField.text!
}

this is butoonaction: if there is no extra row then also it says please enter amount, if there no added row then i dont need enter amount alert, i want enter amount alert only if there is added row

  @objc func buttonClicked(sender: UIButton) {
    //let buttonRow = sender.tag
    print("in newbiller search button")
    print("the amount value \(finalSearchValueAmnt)")
    print("the phone value \(finalSearchValue)")

    if self.finalSearchValue.isEmpty{
        AlertFun.ShowAlert(title: "", message: "Please enter \(self.alertParam!)", in: self)
    }
    else if self.textCount ?? 0 < self.alertMinL ?? 0{
        AlertFun.ShowAlert(title: "", message: "\(self.alertParam!) not lessthen \(self.alertMinL!)", in: self)
    }
    else if self.textCount ?? 0 > self.alertMaxL ?? 0{
        AlertFun.ShowAlert(title: "", message: "\(self.alertParam!) not graterthen \(self.alertMaxL!)", in: self)
    }
    if self.finalSearchValueAmnt.isEmpty{
        AlertFun.ShowAlert(title: "", message: "Please enter Amount", in: self)
    }
    else{
    billerFetchService()
    }
}

please help me in the above code, to validate added row textfield.