When called and no-one answers, my phone plays the pre-recorded answer/record announcement but then only records about 10 seconds of the caller's message before switching off.
Ah, 'lucky' you! Ours quite often goes through the announcement and then records no message at all, even though people think they have. This is rather irritating!
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cordless phones.