Use watchmaker in my other Google account

So I've been using my Google account for few years now and bought watchmaker premium on it. Although I've started to use different account now on which I do have some Google credits to use. I've uninstalled WM and redownloaded it from this new account and also bought premium from new one. Signed up with new account but payment methods are still pointing me up to the old account (one without any Google credit). Did I just waste £5.99 for premium?