This is a Dutch forum where Dutch and English is spoken. I've translate your message:

Goedemiddag Vertel mij alstublieft, is het nummer +31 6 87 31 xx xx uw officiële nummer? Kun je vertrouwen?

This is not a phonenumber of KPN. Probably from a scammer.

Hi! Is a contact in a photo your company? Can I trust this contact?

Admin: topic samengevoegd met bestaand topic

Admin: gegevens verwijderd i.v.m. privacy

​@Isroil Can you tell us more about the context?

Where have you found it? From a SMS/WhatsApp? Or..?

Hi ​@Isroil,

This is a normal Dutch mobile phone number, so I'd like to hear a bit more information, like ​@AriënC already asked. It's possible it is the number of a KPN mechanic, or the number of your contact if you happen to have a ‘groot zakelijk’ subscription. 

We don't use mobile phone numbers for our normal customer service!

This contact made me an offer to buy equipment (phones, headphones). This contact is represented by a representative of your company. This number is from the telegram messenger

KPN does not just contact people via telegram. I strongly suspect that this is a scam.

We do not do business like this ​@Isroil, I agree with ​@AriënC that this really does sound like a scam