Issues buying coins through the web

I first attempted to buy coins in May using PayPal, but it wouldn't go through. I then tried with my debit card, but it again wouldn't go through. Venmo was the last option and it worked... for a while. Now I get purchase decline.

I called Venmo and they said there is a system lock and they couldn't override it. I am guessing there is some automated security feature if I spend more than $500 total in a month? I am in the US. Anyone experience this? I am still able to purchase using the app, but the coins are more expensive there.