I have some expiring money trapped on a GSM phone. Use-it-or-lose-it. I cannot see how to spend it all at the last minute.

Anyone know of any clever ways to use phone credit?

I think there would be no problem if this were Africa because a lot of people there have no bank account; they use their GSM phones for banking instead.

Update: I found a business that sells the “Premium SMS” service to other companies who want to accept payment in that way:

https://www.cellcom.eu/en/sms-services/11/premium-sms/

But sadly, there is no list of their customers.

So far, I have only found De Lijn, parking, and shitty US tech giants (e.g. Google Play Store) who can take payments via premium SMS.