A reply they gave ...
Unfortunately when trading on an ECN execution times can vary and we do not offer any sort of guarantee of execution times.
Pepperstone is a 'Market Execution' broker and as such we are at the mercy of the market to what execution we can give you. If a Bank takes a long time to fill your trade then unfortunately we cannot do much about it. This is one of the realities of ECN trading in Forex - You are trading with multiple counter-parties in a whole host of different locations with different infrastructure.
Possibly your trade was a victim of the 'last look' rule/functionality in FX Trading.
Last look is where the FX dealer (Bank) who is providing you with the price gets a change to review your order before he/she accepts it.
In RFQ-based trading, it's where a trader gets a chance to equal or better the market when an indicative price is hit.
'Last look' refers to the feature on many platforms in which the party that is making markets (Usually a Bank Counter-party) gets a chance to reject a trade if it doesn't want it.
Generally, the Bank has a couple hundred milliseconds to reject, or the fill is good. It's a lamentable practice that has its origins in the early days of e-Trading, when bank technology was so much slower than on the buy-side (institutional prop trading and retail fx brokers like us), that this had to be added so that banks wouldn't be hit so badly by wild algorithmic trading. Even though banks have mostly improved their infrastructure, they became addicted to having last look at trades, so the practice persists. Most major platforms ECN's and Aggregators still support it.
Market Maker brokers use 'Instant Execution' which means that the trade is immediately filled as soon as it hits their MT4 server, In some situations Instant Execution brokers have faster execution but they also often give 're-quotes'.
Unfortunately fills and execution times like this are beyond our control and are product of offering an ECN service to our clients and in this situation we are unable to refund trades.
"Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time. -Thomas Edison"