Is the contract for people who install photovoltaic devices for free to send text messages on their mobile phones valid?

Is the contract for people who install photovoltaic devices for free to send text messages on their mobile phones valid?

Legal analysis: SMS contract is valid. Because this form of contract, like other data message contracts, has the defect that it is difficult to distinguish authenticity, although the contract is valid, it is best to sign a paper written contract later. However, the acceptance of the contract offer should be made within a reasonable period of time. Unsatisfactory performance cannot be regarded as a contract.

Legal basis: Article 469 of the Civil Code of People's Republic of China (PRC), the parties may conclude a contract in written form, orally or in other forms. Written form refers to contracts, letters, telegrams, telexes, faxes and other forms that can tangibly express the contents contained. A data message that can tangibly express its content through electronic data interchange, e-mail, etc. , and can be retrieved at any time, are considered in writing.