Fridge freezer ice block nightmare

[Girlpower55]

An ice block forms at the back of the fridge part of my fridge freezer and blocks the drainage gully, eventually blocking the drainage hole too. I have to clear this ice about every 5 days to prevent flooding at the bottom of the fridge. I don't want to turn the fridge temperature down as it is already running above the recommended temperature.
Any ideas for a fix please