He has old bills that he did not pay and he has not been asked to pay them; does he have to pay them?
Question

I have some old bills for the Saudi Telecommunications Company, and no one has asked me to pay them. I do not know if they are still with me or not? I am afraid that this will be a debt that I still owe if I do not pay them. Is there any blame on me or do I have to do look for them and pay them, because I still owe them, or do I no longer have to pay them?
Praise be to Allah.Islam teaches us to give people their dues and forbids us to consume people’s wealth unlawfully. Allah, may He be exalted, says (interpretation of the meaning):
{O you who have believed, do not consume one another's wealth unjustly} [an-Nisa’ 4:29]
{And do not consume one another's wealth unjustly or send it [in bribery] to the rulers in order that [they might aid] you [to] consume a portion of the wealth of the people in sin, while you know [it is unlawful]} [al-Baqarah 2:188].
Ibn ‘Abbaas (may Allah be pleased with him) said: This has to do with a man who owes money and there is no proof of it, so he denies the debt and argues with the judge, when he knows that he owes the debt and he knows that he is sinning and consuming unlawful wealth."(Tafseer Ibn Katheer  1/521).
The Prophet (blessings and peace of Allah be upon him) addressed the people on the Day of Sacrifice and said: “Your blood, your wealth and your honour are sacred to one another, as sacred as this day of yours, in this month of yours, in this land of yours.” Agreed upon.
An-Nawawi said:
What is meant by all of that is to affirm and emphasise how sacred people’s wealth, blood and honour are, and to warn against any transgression thereof. End quote.
The Permanent Committee for Ifta’ was asked: Is it permissible to use tricks to avoid paying bills for electricity, water, telephone service, gas and the like? Please note that most of these things are provided by companies whose shares are held by ordinary people.
The committee replied:
That is not permissible, because it comes under the heading of consuming people’s wealth unlawfully and not rendering back trusts. Allah, may He be exalted, says (interpretation of the meaning):
{Indeed, Allah commands you to render trusts to whom they are due}[an-Nisa’ 4:58]
{ O you who have believed, do not consume one another's wealth unjustly but only [in lawful] business by mutual consent. And do not kill yourselves [or one another]. Indeed, Allah is to you ever Merciful} [an-Nisa’ 4:29]. "(Fataawa al-Lajnah ad-Daa’imah  23/441).
Moreover, al-Bukhaari (13) and Muslim (45) narrated from Anas (may Allah be pleased with him) that the Prophet (blessings and peace of Allah be upon him) said: “No one of you truly believes until he loves for his brother what he loves for himself.”
So examine yourself: would you like it if someone owed you something, then he denied it or concealed it so that it would be hidden from you and you would forget it? Or would you like him to pay it back, and for him to give it back to you and return it to you?
You should understand that if people’s rights are not given to them in this world, they will be given to them on the Day of Resurrection.
Muslim (2582) narrated from Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (blessings and peace of Allah be upon him) said: “You will certainly pay the dues to all those to whom you owe anything on the Day of Resurrection.”
So what you must do is pay off these bills.
If you cannot find the bills, then you may refer to the company and ask about these bills.
For more information, please see the answer to question no. 70274 .
And Allah knows best.