ApexLeoTur10 Unfortunately there is no way to refund or exchange an unwanted Heirloom, (which has been something that many players have been wanting since the introduction of Bloodhound's first Heirloom).
However, if you have been playing the Creator Takeover event, two weeks ago there was individual challenges to earn 20 free packs from Ninjayla's creator challenges, and for this week, there is another set of individual challenges to earn 20 more free packs from Oraxe's creator challenges.
There also will be two more creator challenges from April 1st to April 14th, (which would be Apryze's creator challenges) and April 15th to April 28th, (which would be Kaminari Kyupi's creator challenges), where if the community completes the community challenges in the first week, the second week of both creator challenges would be two more individual challenges to earn 40 more packs, (which would be 20 packs each for the two creators).
If you had earned the packs from Ninjayla's creator challenges, and earn the packs from Oraxe's creator challenges this week, (as well as earn the remaining two creator's packs, (should the community complete the community challenges for the next two creators)), you'll be at 80 free packs, (which means its possible to get more Heirloom shards).