send string(textbox) to arduino from website..... (esp8266)

hello guyx i hope you guyx are fine!
i want to send a string from my website to the arduino mega which has esp8266 ("AT" commands working fine)
guide me to some tutorials plzzz
i have time i will study
i tried blynk to do my job done but it gives esp8266 is not responding
then i tried thingspeak talkback app but it also doesnt seem feasible cause you cant send strings with it, it only act on commands, which are already stored or something but i tried it, just saying,

clearing stuff

i need a textbox input in website or andriod app, so the arduino receives it and show it on lcd16*2...
plz guide me plz what tools should i try what specific thing should i study
blynk and thingspeak doesnt work tried