From your description, it appears that you advanced a sum of money to your gym trainer based on a hand loan agreement and promissory note, with an assurance of return of the principal amount along with a share in profits. The fact that the payments were made through bank transfer and that written documents exist is in your favour and constitutes strong primary evidence.
You have two parallel remedies available in law — civil as well as criminal.
On the civil side, you may initiate a suit for recovery of money on the basis of the promissory note and loan agreement. Such a suit can also be filed under summary procedure (Order XXXVII CPC), which is comparatively faster where written instruments like promissory notes are involved. You may claim the principal amount along with interest and any agreed return, subject to proof.
On the criminal side, if it can be shown that the intention to cheat existed from the very beginning (i.e., he induced you to part with money without intending to return it), you may file a complaint for offences such as cheating and criminal breach of trust. Given that there are multiple victims and a pattern of conduct, this strengthens the criminal case.
As regards jurisdiction, ordinarily, a civil suit would be filed where the defendant resides or carries on business (i.e., Bangalore, where the gym is located). However, if part of the cause of action arose in Coimbatore (for example, if payments were made from your bank account there), jurisdiction may also be invoked. Similarly, for criminal proceedings, a complaint can be lodged where the transaction occurred or where the consequences ensued. This aspect will need to be assessed carefully based on documents.
Your concern about false counter-cases is understandable. While such tactics are sometimes used to pressurise complainants, they do not automatically weaken your case. Since your transactions are documented and traceable through banking channels, your position remains legally strong. It is advisable, however, to proceed through proper legal channels and avoid any direct confrontation.
In terms of time and cost, civil recovery proceedings in India may take time (often a few years), though summary suits can be relatively quicker. Criminal proceedings may also take time but can exert pressure and sometimes lead to settlement. Legal costs will depend on the forum and counsel engaged, but given the amount involved (₹2 lakhs plus additional ₹1 lakh), it is generally considered worthwhile to pursue recovery, particularly when documentary evidence is available.
As a first step, it is advisable to issue a formal legal notice demanding repayment within a specified time. This often leads to settlement and also strengthens your case if litigation becomes necessary.
Please feel free to reach out should you require assistance in drafting the legal notice or initiating appropriate proceedings.