How much do you know about PHP / SQL databases? If you know how to do it with SQL then it's just a case of using a different database drive for Access:
The above URL gives examples.
Someone types in a complaint in a text field on the website and it is sent to database.
You'd typically have a server side application running that'd receive the results of the form via a GET / POST request - the server side application can then choose to do what it likes with the data, including adding it into another database.
Usually these are done in PHP, though Java servlets are another option. Have a Google around for PHP / Servlets and databases and you should find some pretty good articles about how to go about things (there's lots around.)
That said, I'd typically advise against using access wherever possible - it's a terrible database system! Oracle is of course the big, paid for corporate giant but I'd honestly recommend MySQL or PostgreSQL (both free) - the former is more popular but the latter is more fully featured (allows you to do OO for example.) If I had to pick I'd use MySQL any day over Access!