I purchase once or teice every month on amazon where mostly I purchase dominos or other instant vouchers.
Customer service: the services is very good and they do respond within a time and try to solve the problems ASAP try live chat for more easy communication
Product quality: it depends on seller.till now what ever I got was all good and I think mostly all are good quality the packing and all are done safely
Delivery timelineness: mostly the delivery is done very fast but some times it take to long to get delevered
App and websites: I recommend to use app instead of website cause they do focus more on development of app where the sudden flash sale as can be done easily without any problem