Apache mod_rewrite querystring problems - .htaccess

Question

I have an old website - written in asp. The contact form uses a querystring to decide which form the visitor sees.
If a vistor wishes to just contact me, they may do so by clicking the link to:
http://example.com/contact.asp
If they wish to submit a fault - they do so by clicking the following link
http://example.com/contact.asp?problem=true&.......
Additional parameters are also passed after problem nb: ?problem=true&Customer... - however, I only need to know if problem=true
In the new site I have two pages: contact.html, and help.html
When a visitor goes to contact.asp they are redirected to contact.html - thanks to the following redirect rule:
RewriteRule ^contact\.asp$ http://example.com/contact-us.html [R=301,L]
However, I am having MASSIVE problems trying to get
http://example.com/contact.asp?problem=true to redirect to help.html
I've found tons of examples - but none of them work.. the page always redirects to contact.html
I have even commented out the above rewrite rule to see if my problem=true rule was being over-ridden.... This returned a 404. My problem=true rule just doesn't work.
I've been following examples such as: http://www.simonwhatley.co.uk/apache-htaccess-query-string-redirects
So to recap, I'd like to redirect contact.asp?problem=true to help.html, and contact.asp to contact.html
Many thanks in advance,
Rob

Answer 1

Not sure what you have tried as far as matching the query string, but the following should work.
RewriteCond %{QUERY_STRING} ^problem=true
RewriteRule ^contact\.asp$ http://primarysite.net/help.html [R=301,L]
RewriteRule ^contact\.asp$ http://primarysite.net/contact-us.html [R=301,L]
Hope that helps.