php - RewriteCond won't rewrite my URL, instead it throws and error 500 -

i trying strip out single level of new written directory avoid repetition of entity names in url. specific name of "well service" duplicated passing both page category , pump category url render page , perform relevant queries.

my current url looks this

http://mysite/wellservice/well-service/pumpid01 

although not major problem aesthetic perspective clean url further stripping 1 level of "well service" url create looks this:

http://mysite/well-service/pumpid01 

i have tried build query handle causes server respond error: 500, query can seen below:

rewritecond %{query_string} ^?id=([\w-]+)&s=wellservice&c=(well-service)$ rewriterule ^product.php/?$ /pumps/%2/%1/? [r=301,l] 

have done wrong in code error 500 returned, or not possible trying do.

note:

• variable "id" = pumps id query database
• variable "s" = category pump belongs to refine query result
• variable "c" = page category generate page specific styling including active state