looking for a temporary virtual number, which service should i use?

So your number changes?

 

I use Hushed and absolutely love it as a secondary number. If I'm selling something online or otherwise have to contact people I don't really know, I use my Hushed number and not my real number.

Remember that if you use any product or service for which you don't pay anything, YOU are the product. You get what you pay for.

 

Vonage or Magic Jack comes to mind. There's Skype as well, that offers virtual phone numbers for many countries with Skype-In.

 

Are you in the US, and have the US as your registered Play Store country? Because AFAIK Google Voice is only available Stateside.

EDIT:

I'm actually in China, but I'm registered for the US Google Play Store and GV is apparently available for all of my devices. Although "Google MBOX" is a T95 Android TV box, and NOT a phone, so no idea how well GV would work on that.

 

IF you trust Google with even more information about you...

 

Dingtone.
Been using it for years, and no trouble using it for account set-up.

It's free, even.

Be sure to maintain it, and use it once a month at least.

https://dingtone.en.uptodown.com/android

When you are done (you said 'temporary'), remember to change the number you opened the account with.