Can Vodafone sell any number which is already in use?

I have been using a vodafone number 30080906 for more than two years. last thursday, i have gone to vodafone office in street no. 23 to change prepaid into postpaid monthly 100 Qr. A person named alsam told me that my service may be not working for 1 or 2 hrs. More 3 days passed, there was no service in my simcard. it was saying invalid sim or registered failed. When i have gone to vodafone office, on saturday, they said that simcard will work with 24hrs. but next day, when i have gone to same vodafone office, they said that my simacard number had already sold. i have bills and every document of it. They said that is the problem of system. they will try to contact me to solve the problem as soon as possible. but they dont. again i had gone to vodafone office, they are again saying to come next day, next time. etc. in this case, what should i do to get my same number? For help and suggestion, u can mail me at :- krishnadevpal/-a-t-/gmail.com or call me at 55743168