To reset a D-Link router, follow these steps:

Locate the reset button on the back of your D-Link router.
Using a paperclip or a similar tool, press and hold the reset button for 10 seconds.
Release the button, and wait for the router to restart. This may take a few minutes.
Once the router has restarted, it will be restored to its factory default settings.
As for D-Link support phone number, it may vary based on your location and the specific product you are using. You can check the D-Link website to find the support phone number for your region and product. Alternatively, you can also try contacting D-Link support through their website or social media channels.