Homebutton won't work in 2 iPhones

Hi,

First I replaced the back cover of my iPhone.

Everything worked but the homebutton, than I did some things about the connection of the flex cable (charger + dock + blabla) and nothing else happened. I pressed on the iPhone and the homebutton works that way. But I didn't want that, did some things again and than the homebutton works but the charging doesn't?

There are weird things.

Somethimes I needed to put the charging cable a couple times (in the same way, same pressure) in my iPhone and than he charged.

I also put some other flex cables inside, even in another iPhone 5 but every time there was something not working.

How?