Need a custom software to do a simple job.

I need a custom software to do a simple job. The basic job flow is simple but it need to be multithreaded, support proxies, and should able to handle large email list size (do not get crashed or freeze). The basic job flows are given below: 1. I have an email list directory (folder) on my computer. This directory have several email list file (.csv). The software will select one email list file, takes one email id from it. 2. Then software add it to a URL string to query for response. (Based on http post method or whichever is better) 3. It check the http header of the response and check for particular word in this response. 4. If check is True, it save the email id in one list and If false in another list. 5. The process will be repeated till it check all email ids from that list. 6. Once the list finished, it check another list from that directory and do it till it finish checking all email ids from all list of that directory. Features needed: 1. We need to be able to define time delay between two queries. Like: 0 time gap (no delay), 0.5 sec or 1 sec 2. Need it multithreaded and should able to process 100 to 200 threads parallel without getting crashed or get freeze. 3. Should support Proxies. 4. Should able to support big email list size without getting crashed or freeze. 5. No bugs. More details will be provided to interested bidder. Please bid only you have good experience with Dot Net software development and have done similar project. Price for this job is also fixed and non-negotiable. Thanks