The UK has already paid £270 million, with the latest £50 million instalment handed over in April. Nobody was deported, although two failed asylum seekers went to Rwanda voluntarily under a separate agreement that saw them offered a £3,000 incentive to go.
Just imagine what useful stuff could have been done with that money.
And this is the key point of right-wing propaganda. Destroy trust into organizations, sow sentiments against immigrants, spread fear by overhyping individual crimes, produce anxiety. Basically "make people angry and fearful".