I asked them to delete my data, they said "Install our app"
A few days ago I sent a GDPR request to some company to delete my personal data. They said to install their app and send a ticket from the app.
The email was sent from the email address to which the account is registered.
Is this even legal?
Being friendly doesn't negate the fact that they are out of compliance with the law. Even sending a second email to insist they delete your data is an undue burden.
You're right, but sometimes a bit of undue courtesy repays in dividends. Not every minor infraction is nefarious and not every minor infraction deserves reporting. A simple courteous reminder of their obligations may save both parties some undue hassle.
I can imagine this company doing this to ensure only authenticated users can have their data removed. There are other ways...but this was probably what they considered reasonable and painless for all, admittedly they (wrongly) didn't consider the audience of this community in that decision.
Remember that you're talking to some poorly paid person that has to deal with unhappy people all day and probably doesn't even agree with these policies. This is no different than being in a restaurant - don't be rude to service people. Be polite, but firm. You can express that you're unhappy and that this isn't acceptable in a way that doesn't come off as berating some first level service drone.
According to my training when I was handling my workplace's GDPR request email companies have 30 days to respond. Meaning they could simply have a bot respond to all incoming emails on day 29 and say "we're reviewing your request" and be in compliance for a while longer