WHMCS Services created a small module of OpenSRS.com that you can check your account balance right from the admin area. That you don't need to login to your OpenSRS account
Commercial support is available for $15 USD
When you buy any of my WS Modules Source Code or License Version you get this FREE or you on existing clients.
If you have any questions at all you can contact us via our group page.
The best place to start if you need help with a specific product is to contact the developer. All WHMCS Marketplace developers have both a website and support URL listed.
Synchronise your invoices, Contacts and Payments with Xero
Integrate your financial data stored in WHMCS into QuickBooks Online.
Automatically transfer your billing & transaction history to KashFlow
Manage your expenses within WHMCS
Allow your customers to receive or download custom account statements via Account Statement WHMCS module.