I would like to upgrade to Tier 4, but that option is no longer available to me, and the sales team is not responding. I have already spent a significant amount of money on credits for my main account. No one is getting back to me; I have no intention of reducing my credit purchases—in fact, I want to continue buying credits to access more hosting capacity via Tier 4, and to upgrade incrementally as my projects grow. Despite this, I recommend the purchase.