If for any reason You decide to cancel the contract on performance of works (rendering of services), you can do it in accordance with the law of the Russian Federation "on protection of consumer rights" from 07.02.1992 № 2300-1.
The consumer has the right to terminate the agreement on performance of work (rendering of service) at any time, having paid to the contractor part of the price in proportion to part of the performed work (rendered service) before receipt of the notice of termination of the specified agreement and having compensated to the contractor the expenses made by it till this moment for the purpose of performance of the agreement if they are not included in the specified part of the price of work (service).
The consumer in case of detection of defects of the rendered service has the right to demand:
Gratuitous elimination of shortcomings;
A corresponding reduction in prices;
The consumer has the right to make claims related to defects of the rendered service, if they are found within the warranty period, and in its absence within a reasonable time, within two years from the date of acceptance of the rendered service;
In case of refusal to perform the contract, the consumer has the right to return the amounts paid to the contractor;
The contractor is responsible for the shortcomings of the service, which does not set a warranty period, if the consumer proves that they arose before its adoption or for reasons that arose before that moment.