Now see it from the company's point of view, why would they contact existing customers and say "hey, we fancy lowering our profit margins - do you want a review of your account?" - I think in the merchant services industry, it is more of a "you don't get unless you ask!" sort of thing..
Merchant account providers are always happy to review existing customers accounts when the customer asks, but a company will not want to spend its resources having a team of people contacting their existing base of customers just to lower their total revenue and profit margins..
Similar to Sky, Virgin, BT, etc.. None of them ring you at the end of your TV/Phone contract do they and say "hey, you've been with us a few years, do you want us to lower your monthly rental?" - however on the flip side, if you get a quote from another company and ring up asking to cancel - they somehow come up with "oh well, we'll lower your monthly rental from £35 to £25 p/m if you stay with us!"..
See what I mean?