You have so far honoured your commitment according to the contract by keeping the material ready. Your client only delayed your work unduly. In the circumstances, you need not fear facing any legal challenge. You have to be ready with all supporting evidence to produce before the consumer forum. In your own interest, as a pre-emptive measure, send out a lawyer's notice demanding fulfilment of your client's part of the contract without any excuse or delay and threatening to go to court to enforce your rights in case of default.