Which vendors of network products like firewalls, routers, switches, VPN softwares and similar are likely to be free from backdoors, already built in surveillance capabilities, secretly broken encryption keys inserted by NSA? Is there an independent vendor that can say no to NSA cheating?
Open source software, like OpenVPN is likely to be free of back-doors. Other than that, depends on how paranoid you are, but it is possible for back-doors to be in everything.
While companies based in other countries may be able to say no, the NSA according to leaks had budget to pay them for cooperation. They could also make it hard for resisting companies to sell in the US, which is a huge market.
Note: As Steffen Ullrich mentioned, there may be hard to find back-doors in open software, such as careful choice of DH keys. To avoid these, you want to generate your own keys and parameters. Using your own will prevent any such back-door. You also don't want to use NIST curves for elyptic cryptography.