Sunnyside Window Cleaning

Sunnyside cleaned my windows last week and although the job they did was ok, I was very disappointed with the customer service. I was quoted $300 over the telephone and agreed to have the windows cleaned. I came home to find a bill for $390 plus tax (less $5 for a window they couldn't reach).
When I called to point out the mistake, they told me I was wrong. It is very poor customer service to ask a client to pay nearly 30% above the price they expected. After a long telephone conversation they charged me $350 - not even splitting the difference.
Poor customer service leaves a very bitter taste and I will not use Sunnyside again.