Didn't get 3 star R5.

So, this era is my first time saving crystals to get the characters to 5 stars. I bought the 5 pack for R5 before claiming the original shards to get him to 3 stars. Now I'm stuck at 2 stars and 13/25. Any way I can still claim the first shards I am missing? I can't level him up or complete any more tiers and I'm F2P so I don't want to just spam buy the packs to catch up.