Trying to make in app purchase but get "cannot connect to itunes"

I bought 40 euro of itunes credit today so i could make an in app purchase on pokemon go. Whenever i try it tells me it cannot connect to itunes. Ive tried everything i could find online and i talked to apple support and did their last resort. Nothing worked it keeps giving me that same message. The guy i was talking to said if it didnt work i should use this code 100003630943 I believe chat support has stopped as i cannot find that option in support anymore. Id like to know what to do as soon as possible. And if nothing at all can help me will i be able to get my 40 euro back or is it wasted?