VMware interview questions

Recruiter called up sounding very enthusiastic about the company. He asked me some technical questions too like what is time complexity of binary search algorithm, what is mutex, what is polymorphism etc. Then he setup a phone interview with an engineer. The engineer spent nearly 30 mins discussing about my resume and a locking problem in multithreading environment. Then he asked me to write code using collabedit. I was not able to complete coding because the interviewer could not clarify in what form he expected the output to be returned from the function. I discussed my algorithm and different approaches that could be used. Why ask an interview question about which you yourself are not clear about the type of output you want. Anyways, never heard back from the recruiter about the feedback on the phone screen. Although I knew they would say "no" since I did not complete the coding, don't they have the courtesy to write a one liner email saying we will not be proceeding at this time. And to the interviewer, make sure at least you know what you really want out of the question. Be ready to give concrete answers for any clarifications to the candidate.