Submissions ignored

[japamor]

I've been submitting free sites for about 3 months now and I keep a record of the acknowledgements, acceptances, rejections etc. that I receive from the LL's. The biggest category belongs to the sites that completely ignore me. I understand that many LL's get swamped by submissions and I don't expect automatic acknowledgements so I check these LL's to see if any of my sites have been listed. A lot of them have listed me . Fair enough. But a lot haven't. No names, I'm not trying to start a war - there's no law to say that submissions have to be replied to. But my reaction after 3 months is to replace these LL's with others. What do other members think - is 3 months too little time.Should I Email the sites to ask what I've done to offend? Do some LL's just not give a shit? Its difficult to know and any guidance would be appreciated.
Cheers,
japamor