Due diligence is definitely important prior to signing a long term agreement. This is also why contracts usually aren't 7 years from the start, usually 2-3 year

Due diligence is definitely important prior to signing a long term agreement. This is also why contracts usually aren't 7 years from the start, usually 2-3 years then longer term once stability is reached. Having payment start from day one is a basic mistake that companies make, usually you can pay for consulting up until the point of go live, then turn on the recurring payment. Making sure bug severity vs resolution time is in writing is another key item to add. Unless you spelled out the SLA and requirements in a contract, you are looking at an ugly court case where you need to claim they are in violation of the 'spirit of the contract'. If they have written down that their service is poor, and you have these examples in writing, it might be possible. As far as rebates go, why would you want to continue a detrimental relationship with a vendor? Usually you would want to exit and find another solution.