Customer service and sales are two important aspects of managing a large business. These two functions are often outsourced. Sometimes that outsourcing is within the U.S. and at other times it is to countries like India. Making sure there are strong communication networks and expectations between the parent and contract company is helpful in giving a positive impression of the business.
Customers don't know the difference between the parent company and the contractor. If the contractor does a poor job it reflects directly on the main company. People will be left with a poor impression that could impact a lifetime of sales. The contract should reflect quality beyond actual sales to ensure customer satisfaction.
Promotions and terms should be well known among all vendors. If the website and the offers are different the business appears to be inconsistent. The impression becomes much worse if promotions offered in advertising pieces are not honored and up sold. The customer may question the integrity of the entire company.
That is the primary point of seamless service contracts that ensure all stakeholders are adequately representing the company. Customers see one business and they care little about about whether or not the company contracted their services. If their needs are not met and it appears they are not being given the latest information they may move over to other business with higher perceived integrity.