I filed my taxes back in feb and still haven't received but when i did i forgot to add my premium tax credit.. I had sent in my missing papers plus the 1040x bout a month after. I had gotten the lette

[Critter]

Well you got issues that only time will solve ... the IRS notice should have  told you to only send the 8962 & 1095-A form to the fax number or address on the notice.  Since you also sent the 1040X it may slow things down especially if you mailed it to the wrong address.   

Now all you can do is wait until the IRS catches up with paper returns now that they are getting back in the offices after being closed for  8 -10 weeks . No mail was opened for weeks ... it has been piling up in tractor trailers so expect your return to take several weeks to process ... check the IRS site every few days ...  https://www.irs.gov/refunds