Update obtain-coretime.md

Removes lastic from docs as project is no longer maintained.

Author: SBalaguer

tutorials/polkadot-sdk/parachains/zero-to-hero/obtain-coretime.md

@@ -48,10 +48,7 @@ With each successful on-demand extrinsic, the parachain will produce a new block
 
 ## Purchase Bulk Coretime
 
-Purchasing bulk coretime involves purchasing a core from the [Coretime Chain](/polkadot-protocol/architecture/system-chains/coretime/){target=\_blank}, which has an instance of [`pallet_broker`](https://paritytech.github.io/polkadot-sdk/master/pallet_broker/index.html){target=\_blank} (the Broker pallet). Although this can be done via sending extrinsics through a tool like Polkadot.js Apps, there are user interfaces for purchasing and managing bulk coretime:
-
-- [RegionX Coretime Marketplace (includes Paseo support)](https://app.regionx.tech){target=\_blank}
-- [Lastic Coretime Marketplace](https://www.lastic.xyz/polkadot/bulkcore1){target=\_blank}
+Purchasing bulk coretime involves purchasing a core from the [Coretime Chain](/polkadot-protocol/architecture/system-chains/coretime/){target=\_blank}, which has an instance of [`pallet_broker`](https://paritytech.github.io/polkadot-sdk/master/pallet_broker/index.html){target=\_blank} (the Broker pallet). Although this can be done via sending extrinsics through a tool like Polkadot.js Apps, the [RegionX Coretime Marketplace](https://app.regionx.tech){target=\_blank}(includes Paseo support) also provides a user interface for purchasing and managing bulk coretime.
 
 !!!tip
     Obtaining a core for bulk coretime on Paseo follows a different process from Polkadot or Kusama. To apply for a core on Paseo, visit their guide for doing so: [PAS-10 Onboard Paras Coretime](https://github.com/paseo-network/paseo-action-submission/blob/main/pas/PAS-10-Onboard-paras-coretime.md#summary){target=\_blank}. 
@@ -104,4 +101,4 @@ Click the **Add Task** button and input the parachain identifier, along with the
 
 You may now select a task from the list. You must also set the core's finality, which determines whether you can renew this specific core. Provisional finality allows for interlacing and partitioning, whereas Final finality does not allow the region to be modified. A core must not be interlaced or partitioned to be renewable, so Finality should be selected if you want to renew this specific core.
 
-Once you sign and send this transaction, your parachain will be assigned to that core.
+Once you sign and send this transaction, your parachain will be assigned to that core.