Trying to implement simple Escrow telegram bot for blockchain.

Here is the funcionality:
1) The buyer sends funds to Ethereum Esccrow Smart Contract.
2) Once the service provided by the seller, The seller receive funds

Here is the stack that I'm going to use:
1) Infura - for interacting with Ethereum mainnet via API
2) Need a service provider to convert fiat-crypto-fiat via api (something like sendwyre - it's not working in my country)
3) DAI - seems the right solution for stablecoin (but read a lot about that commisions are too high)