for tennis, i've always used the same url that the website uses:
https://ips.betfair.com/inplayservice/v ... ionCode=UK
So, if using your api code, just substitute the eventIds with the id that you require. You can also use a website such as: https://jsonformatter.curiousconcept.com/
to validate the json. from thewre, depending on your language, you can go to one of the many online tools that convert json to the required class structure for your language.