My purchase is not recognised

There's no Piktures account: your plan comes from Google Play. Piktures checks it each time it starts, each time you open the More tab, and after a purchase.

Check first

The Play Store uses the Google account you bought with. Open the Play Store, tap your profile icon, and switch accounts if needed. Then come back to Piktures and open the More tab.
The payment is complete. A pending payment counts only once Google Play confirms it.
The phone is connected to the Internet.

Your plan shows as not verified

When Google Play doesn't list your plan, but this phone had already verified it, Piktures keeps it for a while:

No ads, Premium, and the former Plus stay active.
Prime stays active for 7 days after its last successful check. After that, the phone goes back to your one-time plan, if you have one, or to Basic.

Meanwhile, the YOUR PLAN banner of the More tab turns yellow and shows your plan followed by not verified, for example Premium — not verified. The More tab icon shows a dot. Tap the banner to see what to do.

Plan not found on your Google account

When Google Play finds no plan twice in a row, Piktures shows Plan not found on your Google account at its next start. The message names the plan this phone had, and lists the steps to switch the Play Store account.

Open Play Store opens the Play Store. When you come back, Piktures checks again.
Close closes the message.
Tick It is normal, don't ask again if you know this plan isn't on your Google account. Piktures then stops showing the message at start, but the yellow banner comes back at the next check.

Restore your plan

In the More tab, tap Upgrade.
Tap the price of the plan you bought.

If the Google account of the Play Store owns this plan, Google Play reports that you already own it, and Piktures restores it. There's no separate restore button.

The Upgrade screen shows what Google Play sees right now. It can show Basic under Current plan while the banner still shows your plan as not verified.

On a new phone, or after reinstalling

On a new phone, or after reinstalling Piktures, your plan only comes from Google Play. If Google Play doesn't find it, Piktures shows Basic, without any message. Sign in to the Play Store with the account you bought with, then open the More tab.

Still not working

Write to us: see Help. Tell us:

the plan shown in YOUR PLAN, and whether it says not verified;
what the Upgrade screen shows under Current plan;
your Piktures version, shown at the bottom of the More tab.