wifi is horrible

When I first signed on with cox, my wifi was running between 4-10 mbps that is when directly in front of the router (that I am leasing from them). hardwire. i may hit 80-90. I called, they came out and after 2 men, 2 trucks and an hour+ working on the line, a new router (though I had just gotten a new router since it was new service) i was running at about 30... Mind you.. there is no interference with the router when I am doing these test. I  test 5" from the router and can never hit over 40 with the average at 30.

They came out again last week and ran a cable directly from the box to the router... same horrible speed.. was then told they need to do additional test, but needed another laptop to verify its not my laptop... (hp pavilion I bought last year)..

I have tested speed on other sites and at times it runs down to 10mbps, but cox told me to only use their speed test to get a "truer" test.. funny, their speeds are always much higher than then other speed test sites...

could it be my laptop? i tested my android and it reports about 5 mbps on the wifi.... 

anyhow.i signed up for and am paying over $70 a month for 100mbps wifi.. and have never gotten it... why, if they cant deliver, do they sign us up for and charge us for something that doesnt exist??