I recently got a new I-Mac and my old scanner doesn't work with it. Who do I contact?

Open Image Capture in your Applications folder and try that.

see > Scan images in Image Capture on Mac - Apple Support

Also check out > Scan images or documents using your Mac - Apple Support

You have two options, really: use a very old computer or get a new scanner - or a printer/scanner.

Your old scanner is obsolete and cannot function with MacOS 10.15 Catalina.

Another possibility is paid third-party software called VueScan. This costs half the price of a new printer/scanner but it is designed to keep old scanners working with modern operating systems. Search the forums here to see if anyone has had success with it before spending you money. Currently they have a contradictory note saying download "VueScan for MacOS Mojave" but that version 9.7.35 can be used with macOS 10.7 to 10.15 (Catalina).

+1 on using Image Capture.