Strand auto spares supply wrong parts to client

Good day

Can anyone please assist with the correct ombud which i need to contact to lay a complaint.Strand auto spares sold me a service kit with the wrong oil.They sent out one of their employees to check which parts to give me.They gave me the wrong parts which i only found out now at Kelfords Somerset West.They gave me Helix 20 w 50 and my 2005 Ford fiesta 1.4i 3 door use Santetic oil.They deny any liability and informed that Kelfords qualified mechanic need to prove the oil caused the problem.I want to contact the ombud in the correct department to assist me please.

I will never reccomend any person to this spares shop as the owner started arguing with me when i informed him aboutthe problem.He sweared raised his voice at me with the direct words.Oil will not f**cking cause the head to make a noise and i have to prove it.He was very unprofessional and didnt treat me as a valued client.

Many thanks

Dawood ***/email - ***