No speaker or microphone, even after I replaced parts

Hi,

My old Nexus 5 (vanilla 5.1.1 not rooted) is malfunctioning.

There is no sound coming from the speaker in the bottom of the phone and the microphone is not picking up any sound when making a normal call and/or recording a video.
The speaker at the top of the phone however, is working. So I hear people in phone calls, but they do not hear me.
Now to the strange part: If I change to the loud speaker while in a call it's the opposite; I can not hear them but they can hear me.
If I connect headphones into the headphone jack I can hear sound both in calls and in video playback.

So to summarize:
Playing video or music (YouTube, video recording, dialer sounds): No sound
Playing video or music (YouTube, video recording, dialer sounds) with headphones: Sound working
Recording video: No sound recorded
Making a phone call: Sound but no microphone
Making a phone call with loudspeaker on: No sound but microphone working
Making a phone call with handsfree connected: Not tested (I have no headphones with mic).

And what's even more strange is that I just replaced the flex cable with the microphone and charging dock and also the entire speaker with new parts from eBay. And guess what... it's still not working!!! :(

Flex cable I replaced: http://www.ebay.com/itm/281669874921
Speaker I replaced: http://www.ebay.com/itm/252003488330

Followed this guide: https://www.youtube.com/watch?v=OPuCmfhzgbg

What now? I really thought the replacement parts would solve this. :crying:

Any help is highly appreciated!

Regards
P-H, Sweden