Ethereum and POA Network externally owned addressescan co-exist on multiple chains. Switch the network to Mainnet to see tokens on Ethereum, and switch to POA Network to see tokens on POA (or xDai to see your balances on the xDai chain).
To switch networks in MetaMask, click on the Network dropdown to select. Note that POA and xDai are not native to MetaMask, so you will need to add them as custom networks. Instructions are below.
POA20 is an ERC20 equivalent of POA that is on Ethereum rather than POA Network. Learn More Here
To swap POA20, it should first be bridged back to the POA Network. Here are some instructions (note gas fees to bridge from POA20 to POA can be expensive, and must be paid with ETH)
What is the POA contract address?
POA does not have a contract address, it is the native token on the POA network (like ETH is the native token on Ethereum). To send, you need to be on the POA network. If you swap to xDai, it will be wrapped POA (WPOA) on the xDai chain. The address for WPOA on xDai is 0x9fe3864F9Ae7cfb5668Dae90C0e20c4C3D437664