Does the steamcommunity market block the client after multiple tries?

Question

I'm making a program in Java to parse data from a webpage on the steam community market. I know that the steamcommunity market blocks connections for a period of time if the connection is accessing the market too many times in a certain period. Right now, my program access a webpage every 250 milliseconds, and it will do that 10 times before switching to another proxy. My problem is that I will still get http error 429 (too many requests) even if I switch proxies. I know that the proxy switching works because I access my ip from http://checkip.amazonaws.com and it will return the ip of the new proxy. Does the steamcommunity market block clients as well as connections? Is there a way around this?

Here is the code:

               switch(proxyInt){
                    case 0:
                        System.out.println("default");
                        break;
                    case 1:
                        System.setProperty("http.proxyHost", "104.238.131.206");
                        System.setProperty("http.proxyPort", "8080");
                        break;
                    case 2:
                        System.setProperty("http.proxyHost", "158.85.241.82");
                        System.setProperty("http.proxyPort", "1080");
                        break;
                    case 3:
                        System.setProperty("http.proxyHost", "45.63.85.44");
                        System.setProperty("http.proxyPort", "3128");
                        break;
                }

                URL whatismyip = new URL("http://checkip.amazonaws.com");
                BufferedReader ins = new BufferedReader(new InputStreamReader(whatismyip.openStream()));
                String ip = ins.readLine();
                System.out.println(ip);

                URL url = new URL("http://steamcommunity.com/market/priceoverview/?currency=1&appid=730&market_hash_name=" + skins[x].substring(46));
                BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
                String gun = in.readLine();

                skinsLowest[x] = moneyLowest(gun);
                skinsMedian[x] = moneyMedian(gun);
                skinsProfit[x] = skinsMedian[x] * .87 - skinsLowest[x];

                lowestPrices[x].setText(skinsLowest[x] + "");
                medianPrices[x].setText(skinsMedian[x] + "");
                String round = skinsProfit[x] + "";
                profitPrices[x].setText(round.substring(0, 5));

                System.out.println("Lowest: " + skinsLowest[x]);
                System.out.println("Median: " + skinsMedian[x]);

                repaint();

                if(x % 10 == 0 && x != 0)
                    proxyInt++;

                if(x == amount)
                    x = 0;
                else
                    x++;