fed up!

I paid this account in 2017. I've sent them the paid up letter at least 5 times and emailed them and called them and even though this account was paid in 2017 , they listed me on itc in the beginning of 2020. they consistantly call me , I explain to the person calling and he asks me to email paid up letter and the cycle begins again. I don't understand how this company gets away with what they are doing.