Bad service from 2022

I requested a coolant flush 2022 February, and i was charged close to R900 for 5l coolant and labour. It comes to my memory now that i was ******. My coolant was never flushed from the drainage plug, they took out a reservoir and added 1L of anifreeze and that was it. Today cooling system problem due to dirty coolant that was not drained properly by guys i trusted.