All above points are valid in terms of customer protection. If you paid by credit card you may also check with your bank if purchases are insured against fraud. If you ordered item A but received item B, which is apparently the case with your rear light, and seller refuses to send you correct one free or charge - it is fraud and your credit card company or bank may reimburse you for that item if you will file a claim. Just an idea for plan B if nothing else works.