GPC is free software and comes without any warranty.
If you want to get professional support, you can hire an individual or a company for providing such a service.
G-N-U GmbH is doing large parts of the development of GNU Pascal. This company offers special support for GPC and can be contacted at email@example.com.
More generally, to find a company or an individual who offers support and other consulting services for free software, look into the GNU Service Directory.