What does copyrights act 1957 do to help me?

If your content is copy right protected no on ecan without your permission copy that , however you need to register for copyright just writting copy right protected won't do

Ok. I'll do it later on after few years. But for now, I published my techniques.

Now, what are the chances that someone like a CA at top level can claim that my techniques work but he already knows it? He doesn't know it for sure cause, did he publish it before me by buying copyrights for his company? 

If your work is not copy right protected, then there are very less chance for you to fight against the menace of data theft or wrongful claimof your work by a third person.

You have to take steps to protect your interests. 

How much does a copyright cost for one simple technique in excel.

You can consult an IP law practising lawyer or an agency to know further details.

Copyrights act 1957 inherently protects me without buying it.

But for additional protection I have to buy ©️.

Considering this, my work is already copyrighted.

This is my opinion.

Copyright does not ordinarily protect titles by themselves or names, short word combinations, slogans, short phrases, methods, plots or factual information. Copyright does not protect ideas or concepts. To get the protection of copyright a work must be original.

Copyright law does not protect ideas or concepts; it only protects the way these are expressed in a particular work. It does not protect the underlying idea, concept, discovery, method of operation, principle, procedure, process, or system, regardless of the form in which it is described or embodied in a work. Written instructions or sketches explaining or illustrating a concept or method, however, are protected by copyright.

You are right that a work is automatically protected as soon as it exists, without any special registration, deposit, payment of fee or any other formal requirement.