Hi Amir,

Firstly 'to have a lot of birthday cards' is an action and not a description but when to use the Passé  Composé and Imparfait is to do with context so a sentence on its own cannot justify either.

You might say for instance -

"Quand j’étais jeune je recevais beaucoup de cartes d’anniversaire mais ce ne n’est pas le cas maintenant."

Hope this helps!