Jo,
According to feedbacks from downloaders, BigFile's main drawbacks are:
1. Current premium users should send you mails to cancel subscriptions.
2. The network is poor. The premium download speed is lower than competitors such as RapidGator, let alone the free download speed.
3. The payment gateway rejects too many legit credit cards and virtual credit card. Because of point 1, users are apt to use virtual credit card in order to cancel the subscription anytime, but your payment gateway rejects them, so they finally choose another filehost.
Now the new brand BigFile has been up for many months. You should take care about the reason that RapidGator's Alexa Rank is still better than yours. Yes, they randomly delete files and cheat affiliates, but their Alexa Ranks is still still better than yours. Even in April, their worst rank is still under 1000. Although you think RapidGator is bullshit, there are still something that you could learn from them. Reviewing the RapidGator's thread, you could find many people complained about the cheat of stats, but affiliates still stick with them. They are not stupid. The fact is that they cannot find any better filehosts which can make so many sales. If there are not any valuable benifits, they can give up RapidGator instead of crying in that thread. If BigFile is really a better choice, they would come here instead of crying in that thread.
I still doubt that the download speed isssue is caused by your infrastrcture, not the issue of the network. You might heard users of other competitors usually complain some file servers such as s12 are down so that users cannot download files from those servers. Filehosts who have such problems often provide the fantastic download speed for premiums. There must be some bottlenecks on your infrastructure because it looks much different than others. At least I saw download traffic are from ddl.bigfile.to, which can be resolved to many IP addresses. Although it can be resolved to many IP addresses, I still doubt something is highly centralized, such as your storage or traffic throttling processes. Before you announced the new brand, almost all uploaders stopped uploading files to Uploadable, so the loading of your servers are almost zero. The premium download speed was ideal then. Hence I conclude the root cause is the scalability of your infrastructure.
I know the payment gateway issue that rejects credit cards and virtual credit cards is not controlled by you, but other items are still able to be improved by you.