I paid $4271 when i thought I paid $427 to a rodent removal company. Do I have any rights to get a partial refund?

I signed, next to my credit card number, for what I thought was $427,00 (the 1 was on the line on the paper. The man continued writing then gave me copy which i did not check. He had added work that was not discussed. I thought I was paying for trapping and removing of rodents and sealing off a few gaps in the existing wire netting around the 619 sf house and spraying for an odor. I was quoted several time by different sales men of same company $289 to $389 max. After I complained, I met salesman at house to go over work done. I was told job was closed and all work completed. I have recorded message stating this. In fact the attic restoration was not touched. I climbed into to attic myself to discover this, something they did not expect me to do. I took pictures. They did then refund me $969.00. I am trying to get back what I feel I was over charged, but still paying for the work that was done. I'm asking for a refund of $2.000 or more. Who do I go to for help? Thanks!