The bank needs to provide API detail of LANKAQR IPG
Currently supported ComBank only but if BOC supported it can be integrated that as well.
There is a number of sites that are using this plugin in large to make their payments. one is https://www.maligai.lk/ you can check that out how it works.
I will add the successful screen as well to the plugin.
Since there was no reply I’m gonna close this.
Do you have their IPG details with you?