Totally shocking and unacceptable service

i just picked up my lawnmower from Mr Lawnmower after they had inspected it and wanted to charge me R1900 for servicing the machine. Even though on the telephone i advised them not to carry out the repairs they still changed parts on the lawnmower. When i went to pick up my lawnmower, they then handed me a packet with my parts and removed their parts in front of me which infuriated me as i did not hand them my lawnmower in this condition. And because i declined for them to carry out the repairs, i received my lawnmower in such a condition. This is totally unacceptable service. i did not tell them to change any parts on my lawnmower and they further damaged by starter assembly as my lawnmower was starting previously. The guy named Rob insisted that the lawnmower wasn't working before although i know that it was working as i have been using it for 8 years which further infuriated me. Rob even went further by stating why did i bring the machine if it was working, i had to re-explain to him why i brought the lawnmower to them although it was him who accepted my lawnmower so he should already know this. The whole experience was utterly unprofessional and i will not recommend anyone taking their lawnmower to such an establishment.