Try texting back (in all CAPS) - EF OFF or STOP ALL.
If that does not work...
Type (in all CAPS) - CHECK and send it to 2474. You will receive a follow up message that will tell you on how to unsubscribe to it.
You (or somebody else) might have visited a website which made you input your phone number. Those webpages could be very tricky and based on the number of complaints, I just wonder why our telcos have not banned such services which resort to obvious deception.
Copied-pasted my answer from the other topic:
Dati may nabasa akong post na itong club content subscription na ito ay yung Gadget Care premium**
Usually kasi 1 month free gadget care lang, kapag hindi mo ito pina-alis magcocontinue ito at ibibill ka nila.
**hindi po ako sure kung tama, kaya mas makakabuti na iverify mo ito sa kinauukulan. Tulad ng pagtawag sa hotline.