I used amazon for purchasing various products many times and I am sharing my own experience whatever I analysed from their services.
Customer Service: They provide a good customer service support for their customers, If you stuck somewhere and do not know how to resolve that issue they will help you to get out of that. They also providing a feedback section so they can improve their customer services. Some of the customer services they providing are: Return & Refunds, Managing orders, Manage Prime, Manage Payment and others. You can contact them by their official contact number given on the website or by just writing an email to their support team.
Product Quality: Always Product quality is not good but most of the times I got genuine product as shown by the seller and if the product is not as it is shown then I returned the product and got my refund within 7 days. You can receive your refund as you want either directly in your bank account or by cheque.
Delivery Timeliness: I received my product on time always. The time mentioned in the order I received it on that time or sometimes before the mentioned time. But in case your order is not delivered on time you can contact customer care and ask them why your product is delayed and it may be possible they may provide you some discount due to delay in delivery.
App & Website: Their website is nicely build and update continuously to fix the bugs, same as their mobile application. They provide mobile application for both android and iPhone. I am using iPhone application and its working properly without any bugs.
Reliability: I think their services and support are very reliable to their customers. I would like to recommend you must buy from this website.