Deleted number from system while still in regular use

Have been using one voice number for over 2 yrs. All of sudden it`s deleted from their system while in regular use. Sent them proof of call log and recent airtime and bundles recharge and they insist it`s out of use of > 120 days. Seems different people dealing with my query one after the other and next one just wrote standard auto reply without digging deeper nor reading previous communication. I`m gutted ,disappointed and totally unhappy with the service. Insisted on getting senior person`s contact-have not been supp**** with that