Forced to pay more than quoted

Be careful using this company, I have been a loyal customer for approximate 11 years servicing my two bikes with them all this time. I have noticed service has dropped over the last couple of years and this weekend was my last with them, My bike needed repair work which they quoted me R5000 after having the bike for two weeks and me having to chase them up after they waited for a back order part I went to collect my bike with the bill having increased to R6500, They told me they made a mistake on the quote! but during the two weeks of having the bike did not take the opportunity to let me know. This has cost them all my future services with them and I was planning on replacing one of the bikes with a new one in the next couple months, so they have lost that sale as well as I will purchase the bike elsewhere. So ensure they give you proper quotes and don't decide to inflate the costs on collection