@chris it
is possible, but the only workaround I can think of isn't cheap. You'd be better off trying to get the company to cough up their local number or Whatsapp info.
To call an 0800 number from abroad, you basically need to somehow make it appear that you're actually calling from within Argentina. There's a mobile app called Numero eSIM that will allow you to do this (I'm sure there are other similar apps, but I'm only familiar with Numero).
Numero allows you to purchase virtual eSIMs and virtual phone numbers from around the world, and the price varies depending on the country. You can then make and receive phone calls via the app, and for all intents and purposes it is as if you are actually calling from whatever country the phone number belongs to. I sometimes use Numero for short trips abroad, because I can purchase a virtual eSIM and make and receive calls from within the app (over wi-fi) without having to go to a local store (for a physical SIM) or use the eSIM slot on my phone. In other words, if I've already used up the traditional SIM and eSIM slots on my phone, the Numero app allows me to bypass my phone's constraints and purchase additional virtual eSIMs, with the limitation being that calls must be made and received via the app, but with the benefit being I could have additional phone numbers "from" 10 different countries if I wanted to.
U.S. phone numbers issued via Numero are fairly inexpensive - I have a U.S. phone number from Numero for $17.99 a year and it allows me to make and receive calls (via wifi) to/from friends, family and companies back in the States. Unfortunately, Argentina phone numbers cost a wee bit more; the price to purchase an Argentina number is $11 per
month (you can cancel at any time). In addition, it's $0.05 a minute to make calls to an Argentina 0800 number, so you'd have to add a couple bucks to your credit balance to cover the per minute cost.
I currently happen to have a Buenos Aires virtual phone number through Numero that I purchased a couple of weeks ago while helping another BAexpats user with some troubleshooting. I cancelled it same day, but it remains active until the end of the one-month billing period, so I just used it to make several successful wi-fi test calls to various 0800 numbers, including Movistar and Personal Flow.
Long story short, it'd be $13 total with Numero to both buy the rights to a Argentine virtual number and also have enough credits to cover 40 minutes of 0800 calling. May or may not be worth it to you depending on how important the business being conducted is or isn't.