The problem you are going to run into is that without a recorded record of the phone call there is no evidence of the promise made by the customer representative. And then secondly they are likely to say that the representative misunderstood the details of the question. The bottom line is that as frequently discussed on these boards is that service providers have a "permissible purpose" to check your credit profile for services ordered. Now if you were just calling to inquire about cost of service and did not place an order that may be a different argument.
The inquiries will remain on your report for two years but are only factored in FICO scoring for one year. And their relative importance lessens during the one year scoring time frame. There is no method to dispute inquiries with the credit bureaus and it is exempted from direct dispute with the service provider. Take it as a lesson learned and a minor frustration. There are bigger deals in credit reporting (and life) to be concerned over.
Starting Score: 500's