You should have waited for the first return to fully process and the tax due paid. Maybe the amended 1,800 was in addition to the original tax due? Does the amended return show the first return payment due?
The amended return should only be the difference you get back or need to pay. You can confirm this by printing your amendment and looking at the 1040X. Line 18 should be your original refund amount and line 21 should be your additional refund. If you paid on your original return it will be on line 16 (but don't include any penalty on 1040 line 38). If there is an amount owed with the amendment, it will be on line 20.
