Vodafone — unable to make isd calls

I have called vodafone on 20th april 2020, i made several calls and emailed them several times explaining about me not being able to make isd calls from prepaid number. Initially they told their network team has to check and i would be contacted by the team but no one has called so far and today is 11th june 2020. I have activated isd calls and have enough balance to be able to make isd calls! Without proper checks or calling me vodafone says it is not their issue! I have tried my sim in different phone already and it does not work! I need vodafone to fix this issue and address it in an effective way!