Very quick at payment, slow on all other websites!

Great value but the slowest, most sluggish network connection ever! Whenever you have to do something on the internet, it's very slow, but move on to their payment section and see your 4G(LTE), that has been as slow as GPRS (506Kbps), turn into 5G (62Mbps or faster!)... why are they so quick to take our money but provide the slowest internet connection?!