At about 4pm on Sunday, a decade of my life disappeared for ever. I logged into my ancient Yahoo email account to try to find an old message from a university friend. A notice curtly informed me that, as I had not used the account for a year, my inbox had been wiped. Yahoo was my first “adult” email account, an upgrade from my halcyon Hotmail years. It chronicled my life from 2000 to 2010; suddenly, all those contacts, conversations and memories were gone – just like that. Yahoo had not warned me, even though I had given it my Gmail details as an alternative address.

Surely there was someone I could talk to about this. There was – but I would have to sign up to a premium service and pay $4.99 (£3.80) a month for the privilege of speaking to a human being. Instead, I contacted the company on Twitter. “This is normal and the emails cannot be restored,” a representative informed me. Yahoo then ignored all my desperate follow-up messages. I was ghosted by a web services provider.

I am not the only person who was blindsided by Yahoo’s clear-out; lots of people are in my position. We have only ourselves to blame, of course: we should have archived anything important; and we should not have trusted a company that styles its name with an exclamation mark. But that doesn’t make the perfunctory deletion of so much personal history any easier. On Twitter, one former Yahoo user noted that their erased inbox included emails from a loved one who had since died; someone else mourned the loss of their angsty teenage conversations.

The moral of this story is: “Back up your stuff.” Many of us treat the internet as if it is a big filing cabinet in the sky, but we forget that we do not have the master key. We forget that most of us have thoughtlessly agreed to terms and conditions that let companies do whatever they see fit with our personal information. Often, we give big tech carte blanche to mine, share and delete our data – and there is nothing we can do about it, because we have given our permission.

The digital economy has fundamentally changed the nature of ownership. Many of the digital things that we think we own are merely being rented: one policy change and our “possessions” become inaccessible or useless. Last year, for example, Microsoft closed its ebook store; all books bought through the service became unreadable. Earlier this year, the wireless speaker maker Sonos announced that it would no longer provide software updates for older equipment, including hardware sold as recently as 2015. This meant that some speakers would become unusable. After an outcry, Sonos backtracked. However, owners of several other internet-connected devices have had their smart products suddenly become dumb. In 2019, the US electronics retailer Best Buy discontinued its line of Insignia Connect products. It offered gift cards to the people who had purchased these gadgets, but not full refunds.

In the grand scheme of things, the loss of a decade’s worth of emails is not the biggest tragedy in the world. But it is a cautionary tale. It is a reminder of how little we own in the digital economy – not even own our memories.

•Arwa Mahdawi is a Guardian columnist