A strange experience with technical support from a domestic service provider

I recently came across an amazing payment service company and wanted to share it with you all. Considering it's a small company, I won't mention its name to avoid affecting their business.

Here's the situation: After upgrading Discuz to version 3.4, the previous payment plugin stopped working (apparently, that company went out of business). WeChat Pay and Alipay for merchants are too cumbersome, so I was looking for an alternative plugin and found this company. Looking at their website, the data seems quite good (see below).

So I installed their plugin. Domain verification, website verification, identity verification, etc., all went smoothly (it seems their verification process isn't very strict; just submitting is enough). After everything was ready, I found the plugin wasn't working. Payment and transfers were successful, but there was no redirection result. So I submitted a ticket in their backend.

Then the following bizarre conversation ensued. Note: Since they hadn't replied to me for over a day, I submitted another ticket asking why they weren't replying. They told me they might have forgotten, which led to the reply on the 28th where they added me on QQ.

Generally, in this situation, their server returns a callback to my server, which my server receives and then redirects. The problem isn't either with their plugin on my server, or they didn't send me the callback. Their troubleshooting methods are also very unprofessional; instead of checking if their service is working properly, they immediately ask for my account for testing. Was my test environment compromised?

But that wasn't all. After adding them on QQ, something even more amazing happened. It seemed like they didn't care about their customers at all.

For a service provider to solve problems like this, I can only think of two things: 1. All their engineers have left, or 2. They might not want to continue. Moreover, they provide highly sensitive payment services; I can't imagine how such servers could be trusted by 70,000 websites.