I bought an Audi A3 headlight
Ouch! I too have an Adui and your question made me shudder! I can remember the time when you could replace a headlamp bulb for about a pound - or perhaps a fiver if it was a sealed beam.
When asking questions here, do PLEASE tell us when and how you paid. Your rights depend upon this. Also upon whether items are new or used, from a private seller or a business, in the UK or overseas. It's so much more difficult to reply without knowing.
eBay and PayPal's buyer protection schemes both last for just 30 days. After that they will not get involved.
Depending upon how you funded the payment your payment provider e.g. credit or debit card issuer may still be able to help. The help they may be able to offer and the time limits vary, best to contact them and ask.
Failing anything else, if the seller is in the UK you may be able to use the Online Civil Money Claims service, but this can be risky and uncertain, especially against unknown eBay sellers who "disappear" or may not even be solvent. I suggest taking advice first from a solicitor or from Citizens Advice.
