Ellie_meg
your relief reminds me of the phrase "In the land of the blind, the one eyed man is king" (or something similar).
You're pleased that a company to whom you paid a deposit in good faith some time back has changed your holiday out of all recognition, failed to ensure the letter (they say) they sent you was received and are prepared to refund you - but haven't yet done so.
It's the bare minimum they are obliged to provide - the thought they may charge you for a cancellation is, sadly, prominent in passenger's minds as a result of the (generally) atrocious manner in which (some) holiday companies manage their affairs.
You should receive your refund within 72 hours - charge them interest on the sum otherwise.