Let me point out a few things with regard to your question:
(1) As per the provisions of the Contract Act, a contract may be written or unwritten. In fact, the contract may be implied also, which means a contract may be inferred from the circumstances or conduct of the parties even if there was no formal contract (whether written or unwritten). Therefore, merely because there was no formal contract, does not mean that you cannot enforce the contract. In the circumstances mentioned by you, there appears to be an implied contract and that can be enforced, more so because you have paid the consideration by bank account transfer.
(2) WhatsApp, Email and phone conversations are also admissible as evidence. This is electronic evidence. Can be proved by producing the original device / content, or by secondary evidence in terms of Section 65-B of the Evidence Act.
(3) The fact that you have paid by bank transfer, will be useful to prove the consideration paid by you.
(4) In these circumstances, it should be possible for you to file a civil case to compell him to perform his part of the contract, of doing the “specific work” (which you have not specified in your question).
Dr. Ashok Dhamija is a New Delhi based Supreme Court Advocate and author of law books. Read more about him by clicking here. List of his Forum Replies. List of his other articles. List of his Quora Answers. List of his YouTube Videos.