If the contract address is changed then the token will be nullified, means it will be having no value & cannot be used. If the team has changed the contract address then there should be a swap happened which probably you have missed. Sometimes you have to manually swap the tokens instructed by the team probably you have to swap through an exchange or sometimes the ICO team just send you new tokens of the same amount as long as you are holding the old tokens in the wallet for which the private key is held by you not an exchange address.