help with a collection agency trying to collect a payday loan

ok i live in PA, i had a PDL out with the seven group... to my knowledge this was paid and closed. i have received several calls from a Mirand Response systems they claim to be a collection agency and they want me to give them a credit card number or my banking info to secure a payment so i dont get served with papers or i dont get arrested. i asked where this company is located and they state they are based out of houston texas, i asked thelady for a licensing number and none could be provided, also i said i needed a letter of the debt sent to my house well she replied with we did send one out months ago which is a lie because i never received such a letter... well after contacting the texas state attorney office, the texas sec of state office, they told me to report the buisness on the BBB i did that and to also put a 90 day fraud alert through the credit reporting companies whichj i also have done, but i guess the point of this is does this Mirand Response System, have a right to contact me and bug me? i live in PA where the loan was illegal to begin with, to technically the collection company could harrass me all day but they have no legal right to take me to court, serve me with papers, arrest me or hurt my credit score coorect? or am i reading to far into everything and i really dont understand how this process works? i need help on this they are harrasing me about it and to the best of my knowledge it is false info because i dont recal anything, even the offices i contacted in Texas told me dont surrender any information until they remail me the original letter about the collection but when i told the lady at Mirand this she said they dont send repirinted letters, thanks to anyone who can help feel free to contact me if there is furthur questions!!