Washing machine draining only during shorter programs.. What could cause this?

Hi all,

I am not really trying to fix this issue, but just to understand better what possible causes there could be for it!

A few weeks ago, our Zanussi washing machine stopped draining the water. It always went through the cycle normally, but some of the water stayed in. However, this could be solved by choosing the separate drain program after the cycle was over- this drained the remaining water.

Since then, after every wash less and less water stayed in, till the point that now during the shorter/smaller cycles no water remains. However, after some longer washes, some of the water still needs to be drained separately afterwards.

So basically, when this issue first occurred, I was the one doing the laundry. My landlord suspects that I had accidentally put something (coins, whatever) in with my laundry and that's what has blocked the drain pump (or something..). He is asking me to pay for half of a new washing machine, and I suppose fair enough, if it really is certain that I was the one who caused it.

However, I am just confused how, first of all, the separate drain program has all through this issue been able to drain the water. And now, the water gets drained even during some of the cycles. If there really is something blocking it, would this be possible?

My landlord thinks that this is because the longer programs use more water, and not all of it is able to get past the blockage. Which sounds kind of logical to me I guess, but I just have no idea how these things actually work. He was also able to see (or feel, by using some sort of a stick) that the pump doesn't spin properly.

Apologies, my technical details regarding the issue are pretty vague, but as I mentioned I'm not looking to fix this- but hopefully someone would be able to shed even a bit of light on this, so that I'd know whether there is any point in trying to argue with my landlord about this or if I should just accept that most likely it was me who caused this.

Thank you!