Stock management not working

https://www.driphacks.com

System Report:

### WordPress Environment ###

Home URL: https://driphacks.com
Site URL: https://driphacks.com
WC Version: 2.6.13
Log Directory Writable: ?
WP Version: 4.7.2
WP Multisite: –
WP Memory Limit: 512 MB
WP Debug Mode: –
WP Cron: ?
Language: en_GB

### Server Environment ###

Server Info: Apache
PHP Version: 5.6.27
PHP Post Max Size: 100 MB
PHP Time Limit: 300
PHP Max Input Vars: 4000
cURL Version: 7.45.0
OpenSSL/1.0.1e

SUHOSIN Installed: –
MySQL Version: 5.6.32
Max Upload Size: 100 MB
Default Timezone is UTC: ?
fsockopen/cURL: ?
SoapClient: ?
DOMDocument: ?
GZip: ?
Multibyte String: ?
Remote Post: ?
Remote Get: ?

### Database ###

WC Database Version: 2.6.13
: 
woocommerce_sessions: ?
woocommerce_api_keys: ?
woocommerce_attribute_taxonomies: ?
woocommerce_downloadable_product_permissions: ?
woocommerce_order_items: ?
woocommerce_order_itemmeta: ?
woocommerce_tax_rates: ?
woocommerce_tax_rate_locations: ?
woocommerce_shipping_zones: ?
woocommerce_shipping_zone_locations: ?
woocommerce_shipping_zone_methods: ?
woocommerce_payment_tokens: ?
woocommerce_payment_tokenmeta: ?
MaxMind GeoIP Database: ?

### Active Plugins (24) ###

Advanced CSS Editor: by Hardeep Asrani – 3.0
Akismet: by Automattic – 3.2
Contact Form 7: by Takayuki Miyoshi – 4.6.1
Custom My Account for Woocommerce: by phoeniixx – 1.2.3
Instagram Feed: by Smash Balloon – 1.4.8
Instock Email Alert for Woocommerce: by Laszlo Kruchio – 1.1.2
Jetpack by WordPress.com: by Automattic – 4.5
Maintenance: by fruitfulcode – 3.3
Min and Max Quantity for WooCommerce: by BeRocket – 1.0.2
Postman SMTP: by Jason Hendriks – 1.7.2
Simple Custom CSS: by John Regan
Danny Van Kooten – 3.3

Compress JPEG & PNG images: by TinyPNG – 2.1.0
Unite Gallery Lite: by Valiano – 1.7.40
Visual Form Builder: by Matthew Muro – 2.9.2
Advanced Flat Rate Shipping Method WooCommerce: by Multidots – 2.3
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WooCommerce DYMO Print: by WP Fortune – 2.5.5
WooCommerce SagePay Form and SagePay Direct Gateway: by Add On Enterprises (Andrew Benbow) – 3.3.3 – 3.3.6 is available
WooCommerce Product Add-on: by Najeeb Ahmad – 2.5
WooCommerce: by WooThemes – 2.6.13
WooSidebars: by WooThemes – 1.4.3
WooCommerce Helper: by WooCommerce – 1.7.2
WP Simple Paypal Shopping cart: by Tips and Tricks HQ
Ruhul Amin
mra13 – 4.2.9

WP-Mail-SMTP: by Callum Macdonald – 0.10.1

### Settings ###

Force SSL: –
Currency: GBP (￡)
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 2

### API ###

API Enabled: ?

### WC Pages ###

Shop Base: ? Page ID is set
but the page does not exist

Basket: #54 - /your-cart/
Checkout: #74 - /checkout/
My Account: #75 - /my-account/

### Taxonomies ###

Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

### Theme ###

Name: Relia
Version: 1.0.7
Author URL: https://smartcatdesign.net
Child Theme: ? – If you're modifying WooCommerce on a parent theme you didn't build personally
then we recommend using a child theme. See: How to create a child theme

WooCommerce Support: ?

### Templates ###

Overrides: relia/woocommerce/archive-product.php
relia/woocommerce/single-product.php

Ok so I have a problem with a certain product in that stock management isn’t working. This is causing a huge headache for us as this product just so happens to be our best seller (coincidence?).

It has some variations and none of which are reducing in stock when customers place an order – we are having to work overtime to keep up and some orders are delayed. This problem does not exist with any other product.

Both “Manage stock” and “do not allow back-orders” are selected, so I cannot fathom why stock levels remain consistent despite orders being placed for it.

If anyone can help with this problem I’d be most grateful – this is causing major grief for us!!

Thank you for your time,

Euan.