The plant that's is not unlocked
Chomper is actually a 'cashium' plant and needs to be purchased from the store.
His usual price is £4.99🇬🇧 but EA were doing a special offer at the time for £0.99p🇬🇧 and Google playstore even gave me a voucher for 50% off so he only cost me £0.49p🇬🇧.
If you paid for Chomper then i suggest that you provide a screenshot of your receipt and player id number to EA HELP CENTER and they should unlock him for you.
You will find that EA gives newbies a lot of seeds for special plants in the hope that players will buy them, imho Chomper is not a particularly good plant and not worth full price.
If you are on android and want free plants, then you can get Google play credit by signing up for Google opinions rewards and sometimes they give you vouchers in the notifications. You can use it in the pvz2 store.
They don't take up much time or give much credit, but it adds up and i could usually do enough to get a couple of full priced plants every year.
Now that i have most of the plants i want, i use that credit to buy ebooks through Google play books, they do some good deals sometimes with books starting at £0.99p🇬🇧
Hope this helps.
