WordPress website credit card api integration

We have a WordPress website integrated with HubSpot, Salesforce, and a Magento One shopping cart. We are a not-for-profit ministry that survives on donations. At present, our online credit card system We have a WordPress website integrated with HubSpot, Salesforce, and a Magento One shopping cart. We are a not-for-profit ministry that survives on donations. At present, our online credit card system is extremely slow and cumbersome. So much so we are losing donations as people give up waiting and trying to figure it out. We wo...