Trouble setting up metatransactions

My team and I are working on setting up metatransactions for our Dapp. I've followed the metatransactions guide, but have noticed that BaseRelayRecipient is deperecated and isn't accessible through import "openzeppelin-solidity/contracts/metatx/BaseRelayRecipient.sol";.
So I've used ERC2771 instead and I'm having trouble understanding how I integrate relayer with it, so that the user doesn't have to pay gas fee.

:computer: Environment


:1234: Code to reproduce

Hey @Deepak! If you want to set up gasless transactions using Defender, you can check out this workshop for earlier in the year.

Hey @spalladino I've followed the same demo but it doesn't seem to be working on polygon mumbai test net

Sorry to hear that! Can you ellaborate on what errors you're seeing?