Do not manually delete the entries in sysmergesubscriptions. Manually deleting these entries can result in not being able to add new subscribers down the road.
To delete a pull subscription to a Merge publication at the subscriber on the subscription database execute sp_dropmergepullsubscription. Then at the publisher on the publication database execute sp_dropmergesubscription. This is covered in How to: Delete a Pull Subscription.
Executing sp_dropmergesubscription at the publisher will not remove the entry from sysmergesubscription but will set the status to 2, which indicates it has been deleted.
If the status is still 1 in sysmergesubscriptions then perhaps you executed sp_dropmergesubscription incorrectly. Make sure to specify @publication, @subscriber, and @subscriber_db. Also, specify a value of pull for @subscription_type.