At this point I suggest you create a new wallet, write down the seed phrase, store it someplace safe, then send all the funds from your old wallet to the new one.
OP is not able to make transaction from his/her wallet.
According to
this post, the wallet he/she is talking about is watch-only.
To OP:
As the name suggests, your wallet is used only for watching the balance and transactions.
If it was possible to export the seed phrase from a watch-only wallet, then it wouldn't be a watch-only wallet.