Why is it so hard to give Google money?
Hmmm... It's hard to gauge without more detailed information but this kind of problem may possibly be caused by the payment processor (I used to work at Google's processor but only had limited interactions with the Google account). The fraud filters at the processing end aren't the most sophisticated and can/will flag a lot of transactions as suspicious. It's hard to get a meaningful manual review because big G's payment volume is enormous and they (the processor) don't have a dedicated team to handle requests for Google so individuals with small accounts don't get addressed unless someone from Google makes it a priority.