I made a payment to buy the product(statistical supprt resistance <<indicator)
but I couldn't buy the product and I just have money left.
Why did you do that?
If you paid, the product is ready for installing in your MT4/5 platform.
Login with your MQL5 community credentials in MT4/5 >> Tools >> Options >> Community tab, then go to the Market tab down in the terminal window and click the Purchased option to install your product.
If you really bought the product so go to your profile - Purchasesto see it:https://www.mql5.com/en/users/nippng/market
If you find the product there so use the instruction on this post #4 about how to install.