Can I change Lightning invoice to pay with regular Bitcoin (on-chain)?

[Sr.Urbanist]

I am trying to pay for my Internet bill in El Salvador on https://sv.mipagoclaro.com/#/.

The problem is they only accept Lightning. I control my keys and have not been able to set up a Lightning node through the Core client.

I believe my options to be:
      1. Setup a Lightning node and add liquidity, connect with others
      2. Install a 3rd party program, but which one allows me to control my keys?
      3. Pay someone I know in Bitcoin to their Chivo wallet and have her pay for me
      4. Use the SWIFT network

or


Is there a way I can convert the BTC Pay Lightning invoice to regular Bitcoin, so I can just send the payment with fiddling around or giving my keys to someone else?

Thank you.

[Rath_]

Is there a way I can convert the BTC Pay Lightning invoice to regular Bitcoin, so I can just send the payment with fiddling around or giving my keys to someone else?

You can use third-party services like Boltz, Lightning Conductor, ZigZag for that. They can pay any Lightning invoice if you pay them via an on-chain transaction. All of these services charge a small fee and they are not instantaneous as your transaction needs to be confirmed first.

[Sr.Urbanist]

Thanks. I was trying to avoid losing control of my keys and have third-party risk. 

It looks like Exodus mobile wallet makes it really easy to move funds to and from Lightning via the Wallet of Satoshi.

[NeuroticFish]

Although I didn't use that, from what I know BlueWallet (for Android or iOS) has the option to create a "Lightning wallet" (a custodial service!) you can top up on-chain and then pay from that one.
This could help OP get a better control over what's happening. And it's one more option to the list.