ITV's 'Teletext' service was switched off 10 years ago. The BBC's 'Ceefax' service was switched off 7 years ago. The BBC Red Button text services will be switched off 'early next year' (although there seems to be no exact date yet).
As Hopkirk suggests, missing Red Button services usually indicate insufficient signal strength. The power output of many Freeview transmitters is being reduced in order not to cause interference to 5G mobile phone signals. In addition, the signal strength at an aerial has never been constant; it's affected by interference by things as close as your neighbour's inkjet printer or as far away as solar flares on the Sun's surface, as well as by the 11-year sunspot cycle, atmospheric pressure, precipitation, path obstructions and much more.
Increasing the signal strength by install one of these
https://www.argos.co.uk/product/9383027
together with one of these
https://www.screwfix.com/p/fly-lead-coaxial-plug-to-plug-1m/41720
will almost certainly fix the problem. However, as has been noted, Red Button text services will disappear altogether within the next few months anyway.