Scotts LawnService

I hired Scott’s lawn to make 6 applications for the season. Their applicator spent about 30 seconds running through the front lawn, and didn’t touch the back yard (even though the contract included all lawn area).
The outcome is horrendous — my lawn is 80% crabgrass, and for this pleasure I paid them $ 500.
I called them over to fix this, and the response I got was that it’s my fault because my lawn wasn’t thick enough to begin with. I called a local trusted landscaper who told me this is not true, and that if they actually did what they were paid to do the result would be much different.
Update 8÷11÷15:
Scott’s lawn representative emailed me and said they will not be making further applications, but will not refund for services that were not performed, but partially paid for, nor will they refund for their scam-​service, since the truck was parked outside my house for 6 minutes (5 of which were spent in the truck).

They do not respect their customers or people’s wishes! Have asked them to take off their call list. Just received my 5^th phone call in a 7 days!
The last phone call I spoke to the «manager» who promised that the calls would stop. I told him that I could understand a mistake or two, but if they continued to harass me I would tell my story on Unilocal.Here is my story.
Last spring a representative from Scott’s Lawn Service came into my yard and offered me a great sales pitch for their lawn services. I said that I liked the idea and would have to talk to my husband as the lawn is his domain and I would call the Rep to let him know.
I was shocked when the Rep. signed me up! I asked my husband that night he said he’d think about it and I got an email welcoming me to Scott’s Lawn Care. I then called the company & complained that I was signed up by mistake (or being signed up against my will, but I would hate to think that they are that sleazy). They apologized and said that they would speak to the representative. Yet, they continue to email me.
I can easily delete an email, but about weeks ago they started calling me asking me to sign up again. The first call I politely explained that I never signed up with them, I was signed up by mistake and that I wanted off of their call list. He insured that he would.
Now they seem to be in the Spring Selling season as they have continued to call me! They called me again about 7 days ago I told them I want off the list. They called 6 days ago I demanded to be taken off of their list. They called 4 days ago I was rude and demanded again to be taken off the list. He assured that he would. When they called 3 days ago I was kind and respectful and asked to speak to the manager and explained and asked him to take me off the list. He assured that he would just like the other callers had.
Would you believe that they called me about 10 minutes ago again! I am mad because I feel that they have no respect. They signed me up against my will, now they continue to call me after I have spoken to 4 representatives and a manager and they all lied and said that they would remove me.
What do I do next? Now I feel harassed.