We are having issue with WHMCS - 2Checkout (Inline Checkout) in recurring payment. If a service has an add-on, WHMCS creates two lines in 2Checkout Subscription as shown in the attachment.
When this subscription runs automatically next month, 2Checkout sends two API calls, one for each part. But the problem is WHMCS only records one part and ignores the other. It doesn't even show in the Gateway logs.
We have been in contact with WHMCS since 06-Mar-2020 (yes for about 2 years now). They found out on 09-Mar-2020 that there's problem in WHMCS and there is a deficiency in the duplicate payment prevention routine of the 2Checkout module (screenshot attached. They opened case #MODULE-7315 but even after about 2 years it is still unresolved.
Our business is based on recurring payments and we have to do lot of manual work everyday due to this.
Can someone please help me how to fix this? WHMCS team doesn't seem to be taking this seriously.
Regards,
Zulqarnain