The Gemara is addressing this point, clearly indicating that it is still Lachem although the Chomesh was not paid. This shows us that although one must pay the Chomesh, it is a Halachah which one must fulfill "Klapei Shmaya" -- "towards Heaven". Otherwise, he has transgressed a prohibition of not paying a Chomesh which the Torah stated he is obligated to pay.

However, once he pays the Keren, the object has fully transferred to his possession, and he is the owner of the Matzah.

All the best,

Yaakov Montrose