Google Video could not dislodge YouTube despite having access to the largest traffic flow in history.
Oracle has had no end of nightmares trying to dislodge SAP as the leader of the ERP market. (Including several giant sized purchases.
And I sincerely doubt that Facebook will ever dislodge Twitter despite having similar functionality in some areas. Just as the reams and reams of companies trying to dislodge LinkedIn have little to no chance of doing so.
It is extraordinarily difficult to dislodge the incumbent. Particularly if you are just offering a variation of what they are already doing.
It is best to establish contact, stay in touch, and look elsewhere. Choose companies where there is no incumbent delivering services in your area. Build the base, build the track record, and strike back when the momentum carries you there.
It can be done, I have done it. But the client needs to want to change first. And they aren't going to be swayed by added functionality, or pricing if they are receiving great service and value from their present supplier.
Your money will be better spent investing in blue ocean space, where you can become the incumbent and enjoy all that brings.