Activating Data Transmission for MMS on Samsung S5610 - GSM/UMTS/Auto Settings?

Hello, my wife has a phone S5610
Somewhere in a year, it does not support MMS. It became more necessary now so I tried to run. I searched the net and it turned out that you need to unblock the data transmission. The phone does not have the option of unlocking the transmission as such.
BOK claims that there is no blockage on their part.
Maybe it's about setting the GSM / UMTS / auto operating mode? The configuration file and manual set up and typing did not help
WAP, MMS, internet - just a MMS and internet just used?
Anyone have an idea - a method?

Auto, in the phone settings enable data transmission (although incoming should be received automatically).

In which network sim card? Do you have GPRS enabled?

@sosarek
In android, I do this and ok, but in this phone in the menu there is no command "enable data transmission" or similar - there is only the choice of GSM / UMTS / auto - supposedly this is to allow the transmission
@nutergsm
Play subscription - a fairly old tariff from before 3 years - annoying that it once worked.
Yesterday in one of the PLAY points was advised to submit an official complaint, because Play changed something in the handling of MMS. I am waiting for a response.