Ideally, there are three ways to get your problems resolved.
1. Contact their customer care service over phone/e-mail.
2. Post your complaint on social media and tag the concerned brand.
3. File your complaint online on websites such as , , etc.
In most of the cases, contacting their customer care service helps especially if you provide them the supporting documents. Speaking over phone is always more effective than through e-mail.
In case, you are not heard and your complaint is still not resolved, try posting it on the concerned brand’s twitter page/FB page. There is a fair chance you will be heard. Companies fear bad mouthing a lot hence they would reply you in all good probability.
The third and the most effective way of reaching them is through third party platforms such aswhich does it for free for the consumers. Such third party platforms have so many complaints against any particular brand. These platforms are more powerful as they have lot of dissatisfied consumers posting their complaints at one place. Brands fear them the most.
Hope I answered your query.