To start things off, let me preface by saying that I have basic computer knowledge but my abilities are not overly-technical in nature.

A little background info on my current issue: my wife needs access to her employer's VPN in order to review and edit documents. The IT specialists (both employed and 3rd-party) have remotely accessed our PC and set the VPN up for us. However, we are still unable to connect to it. These IT specialists have told us that it is a problem with our ISP blocking the outgoing traffic.
We have the TCP port numbers (no ranges provided) that are needed to connect to the firewall in order to access the VPN.

After speaking with the ISP, we were directed to the manufacturer of our router. The support dept directed me to the router firmware, where I accessed the port triggering/forwarding interface. There a range of ports is available for input; NOT individual ports as the IT department of the employer has stated.

Should I also try other avenues or actions? Am I doing anything wrong?
Any advice on how to proceed would be appreciated.

Thank you.