Mam problem zapisem po wybraniu z selecta co robię źle

A to skrypt zapisu ajax
<script type="text/javascript"> $(document).ready(function(){ $('#autoSubmit').submit(ajax); }) function ajax(){ $.ajax({ url : 'zapis_danych.php', type : 'POST', data : $('form').serialize(), success: function(data){ $('#resultado').html(data); } $("#maska").show(); $("#maska").prepend(' <img style="margin-bottom: -17px;" src="../images/ajax-loading.gif" />'); }); return false; } document.forms["#autoSubmit"].submit() window.onload=function(){ setInterval(ajax, 5000); } </script>
A tak wyglądają dane do zapisu
if ($product['opis_towaru']){ echo" <input name='cena_min_towaru' type='hidden' class='form-control' id='sumuj' value='". $product['kwota_dodatku']."' placeholder='' style='width:410px;'>"; echo" <input name='min_towar' type='number' class='form-control' id='formGroupExampleInput sumuj' value='".$min_towar."' min='".$product['min']."' max='".$product['max']."' pattern='[0-9]' placeholder='' style='width:410px;'>"; echo"<select id='inlineFormCustomSelect ' name='cena_towaru' class='form-control' style='width:410px;'>"; echo" <option value='".$product['cena']."'".($product['cena'] == $cena_towaru ? " selected='selected'" : "").">".$product['opcja']."</option>"; echo"<option value'".$product['cena_1']."'".($product['cena_1'] == $cena_towaru ? " selected='selected'" : "").">".$product['opcja_1']."</option>"; echo "<option value'".$product['cena_2']."'".($product['cena_2'] == $cena_towaru ? " selected='selected'" : "").">".$product['opcja_2']."</option>"; echo"<option value='".$product['cena_3']."'".($product['cena_3'] == $cena_towaru ? " selected='selected'" : "").">".$product['opcja_3']."</option>"; echo"<option value='".$product['cena_4']."'".($product['cena_4'] == $cena_towaru ? " selected='selected'" : "").">".$product['opcja_4']."</option>"; echo"<select id='inlineFormCustomSelect ' name='cena_towaru_1' class='form-control' style='width:410px;'>"; echo" <option value='".$product['cena_5']."'".($product['cena_5'] == $cena_towaru_1 ? " selected='selected'" : "").">".$product['opcja_5']."</option>"; echo"<option value'".$product['cena_6']."'".($product['cena_6'] == $cena_towaru_1 ? " selected='selected'" : "").">".$product['opcja_6']."</option>"; echo "<option value'".$product['cena_7']."'".($product['cena_7'] == $cena_towaru_1 ? " selected='selected'" : "").">".$product['opcja_7']."</option>"; echo"<option value='".$product['cena_8']."'".($product['cena_8'] == $cena_towaru_1 ? " selected='selected'" : "").">".$product['opcja_8']."</option>"; echo"<option value='".$product['cena_9']."'".($product['cena_9'] == $cena_towaru_1 ? " selected='selected'" : "").">".$product['opcja_9']."</option>"; echo"<textarea class='form-control rounded-0' id='exampleFormControlTextarea2' rows='3' style='width:410px;'></textarea>"; }else{ echo" <input name='cena1' type='hidden' class='form-control' id='sumuj' value='". $product['kwota_dodatku']."' placeholder='' style='width:410px;'>"; echo" <input name='cena1' type='number' class='form-control' id='formGroupExampleInput sumuj' value='".$min_towar."' min='".$product['min']."' max='".$product['max']."' pattern='[0-9]' placeholder='' style='width:410px;'>"; echo"<option value'".$product['cena_1']."'".($product['cena_1'] == $cena_towaru1 ? " selected='selected'" : "").">".$product['opcja_1']."</option>"; echo"<option value'".$product['cena_6']."'".($product['cena_6'] == $cena_towaru6 ? " selected='selected'" : "").">".$product['opcja_6']."</option>"; echo"<textarea class='form-control rounded-0' id='exampleFormControlTextarea2' rows='3' style='width:410px;'></textarea>";
A tu mam forme zapisu zapis_danych.php
require_once 'funkcje.php'; $result = dbquery("UPDATE ".$db_prefix."wybrany_towar SET opis_towaru='".$opis_towaru."', cena_towaru='".$_POST['cena_towaru']."', opis_towaru_1='".$opis_towaru_1."', cena_towaru_1='".$_POST['cena_towaru_1']."', min_towar='".min_towar."', cena_min_towaru='".$_POST['cena_min_towaru']."' WHERE wybrany_towar_id='".$_GET['product_id']."'");
Proszę o pomoc.