"whenever we order it gets rejected and escalations only report max 300mbit."
Have you tried ordering through different providers? Some of them may have limited cablelink capacity at your headend exchange, and are limiting orders there, but others may not be capacity constrained.
The ECI footprint is only about 50,000 properties I believe, out of about 10 million now, so you'd be very unlucky to be on one of these.
"escalations only report max 300mbit"
It seems you've already had your answer, although it would be good if the escalations could have explained to you the reason.
In the end, my advice would be to order 330/50. You'll save yourself quite a lot of money over a 1000/110, and probably not notice the difference (unless you're doing lots of uploads, but even then it's only a factor of 2). Most home wifi networks are unable to handle more than 300-400Mbps anyway.
Use the saved money to buy more tea and biscuits for the slightly longer time you'll have to wait for transferring huge files