It's best practice for jetton transfer to include "forward_ton_amount" into transfer message, resulting sending "transfer_notification" message to "main" wallet address, so you can scan incoming tx of your wallet in question and find jetton transfers. But that behavior is not mandatory.
If you have whitelist of all Jetton (Master accounts) you want to support/display - you may call [get_wallet_ad...
When someone creates new Jetton using minter.ton.org, the multiplier (precision) must be specified in corresponding input field ("The decimal precision of your token (9 is TON default)").
For later, you must read Jetton metadata to know this value.
Specification of "transfer" message: https://github.com/ton-blockchain/TEPs/blob/master/text/0074-jettons-standard.md#1-transfer
Sure:
- Jetton Master contract deploys Jetton Wallet contract for receiving user: https://github.com/ton-blockchain/token-contract/blob/main/nft/nft-collection.fc#L45
- NFT Collection contract deploys NFT Item: https://github.com/ton-blockchain/token-contract/blob/main/nft/nft-collection.fc#L45
What is "tpay1 wallet"? Do you know that TON wallet may have different types and if you used some mnemonic to work with one version of wallet - you'll get different address (and different wallet) if you use same mnemonic with different version?
You can check version of your wallet using explorers. After that, you need to use App that supports this version or transfer your treasures to address with "updated version" (for same mnemonic).