I was worried by your post. Having left the acidic mud on my car for a fair few days I was expecting the worst.

Came off a treat at the local jet wash with nothing left behind.

I would stongly suggest that the recent work you had done was not of the required quality if the mud caused damage.

HTH
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Not sure why were are using this medium, but as this topic has come back from the dead I would like to add to to it.

I had a problem with my car when it back from the main agents for a paint job, and it went wrong with an overspray. The overspray was removed, I was told with a "wash" the wash was so good that it even removed the swirl lines that came with the car.

Once the car was home I re washed the car ( with plain water) and the colour of the paint work was evident on the cloth! So I applied a anti uv to the paint job,(red car) then a wax, then a gloss to prevent paint deteriation.

All was fine, I waxed it again prior to going to BH, after reading the original post I washed my car in the morning with copious amounts of water so not to scratch the car, however I too was left with a grey mark on the paint that i managed to soap off and re-polish so said no more.