Well I have no way of telling what has gone wrong, and you do not mention what type of worms you have been buying!

This article I have written might help you to see where you have gone wrong;

http://www.thegardenersalmanac.co.uk/Data/Wormery/Wormery.htm

BTW the cheapest way to buy 'brandling' worms is from a fishing tackle shop, rather than a specialist who generally charge 'premium'prices.

as the temp drops the worms will migrate downwards. They found their own way into the compost bins and i noticed today that there were very few near the top.

Thanks for that SBG, I noticed the other day my usual red worms werent around the top of the compost and did wonder why they had gone, good to know they are still there.

Thanks for that. Have read your article, which is helpful and informative, but still doesn't solve the mystery as to why my worms completely disappear within a few weeks. Have followed the steps you suggest, but they still don't like me! Anyone got any ideas what the cotton ball thingies are? Anyway, thanks everyone for your contributions. Maybe I should give up and keep ferrets instead .....

cotton ball thingies sound like spider egg sacs. they are nothing to worry about and wont do any harm to worms. It is as I said the drop in temp and they should reappear next year.

Thank you, seaburngirl for your second answer. Unfortunately, it still doesn't quite fit. As I explained in my original question, I had the wormery at Christmas, within weeks almost all had disappeared, so sometime in spring/summer I received a replacement bagful and they promptly disappeared, too. So a drop in temperature really doesn't seem to come into it. And no, there are no worms in or under the lower trays. Because there have been so few - or even none at all - there is very little compost for anything to hide in so it's very easy to see (particularly after a gentle stir) what is - or in this case isn't - lurking in there. So I guess the mystery will remain just that - a mystery.

What materials are you adding? too much citrus peel [acidy] would upset the balance of the pH. Worms are sensitive to acid conditions. I notice you said you used cardboard to absorb moisture did you keep it slightly moist as they need it moist/damp to get their oxygen. if neither of these fit them I'm stumped. Late frosts/ clever hedgehogs having a munch?

To seaburngirl: I don't add any of the citrus or onion family, only brassica leaves, carrot tops and the like. I add cardboard to soak up excess moisture - even then, it is always very very moist. Can't be hedgehogs 'coz it's a proper wormery, three-tiered fully enclosed plastic containers set on top of ten bricks. Nor is it likely to be late frosts, not only because that first year we had a particularly warm spring, but also because on reflection I realise I took delivery of the second batch of worms in May/June. I'm stumped, too! As I said originally, I have followed the instructions to the letter, I've rung the suppliers (who are equally at a loss), yet for some reason my worms simply leg it. I read of all these people who are having to give away excess compost or sell excess worms and I feel a complete and utter failure! What's that saying? Nobody loves me, everybody hates me, guess I'll go and eat worms! Is there anybody who can tell me where I'm going wrong???