diff --git a/.tool-versions b/.tool-versions
index be2e95640..7533e0973 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -10,7 +10,7 @@ golangci-lint 1.55.0
 actionlint 1.6.12
 shellcheck 0.8.0
 scarb 2.5.4
-postgres 13.3
+postgres 15.1
 
 # Kubernetes
 k3d 5.4.4
diff --git a/monitoring/pkg/monitoring/source_envelope.go b/monitoring/pkg/monitoring/source_envelope.go
index 323bdf788..5d833eb77 100644
--- a/monitoring/pkg/monitoring/source_envelope.go
+++ b/monitoring/pkg/monitoring/source_envelope.go
@@ -168,14 +168,14 @@ var zeroBigInt = big.NewInt(0)
 func (s *envelopeSource) fetchLinkBalance(ctx context.Context, linkTokenAddress, contractAddress *felt.Felt) (*big.Int, error) {
 	results, err := s.ocr2Reader.BaseReader().CallContract(ctx, starknet.CallOps{
 		ContractAddress: linkTokenAddress,
-		Selector:        starknetutils.GetSelectorFromNameFelt("balanceOf"),
+		Selector:        starknetutils.GetSelectorFromNameFelt("balance_of"),
 		Calldata:        []*felt.Felt{contractAddress},
 	})
 	if err != nil {
-		return nil, fmt.Errorf("failed call to ECR20 contract, balanceOf method: %w", err)
+		return nil, fmt.Errorf("failed call to ECR20 contract, balance_of method: %w", err)
 	}
 	if len(results) < 1 {
-		return nil, fmt.Errorf("insufficient data from balanceOf '%v': %w", results, err)
+		return nil, fmt.Errorf("insufficient data from balance_of '%v': %w", results, err)
 	}
 	linkBalance := results[0].BigInt(big.NewInt(0))
 	if linkBalance.Cmp(zeroBigInt) == 0 {
diff --git a/monitoring/pkg/monitoring/source_envelope_test.go b/monitoring/pkg/monitoring/source_envelope_test.go
index 0833f37c5..dfb9b7034 100644
--- a/monitoring/pkg/monitoring/source_envelope_test.go
+++ b/monitoring/pkg/monitoring/source_envelope_test.go
@@ -63,7 +63,7 @@ func TestEnvelopeSource(t *testing.T) {
 		mock.Anything, // ctx
 		starknet.CallOps{
 			ContractAddress: chainConfig.GetLinkTokenAddress(),
-			Selector:        "balanceOf",
+			Selector:        "balance_of",
 			Calldata: []string{
 				starknetutils.HexToBN(feedConfig.ContractAddress).String(),
 			},
diff --git a/relayer/pkg/chainlink/ocr2/client.go b/relayer/pkg/chainlink/ocr2/client.go
index abcc6c112..ecfff3459 100644
--- a/relayer/pkg/chainlink/ocr2/client.go
+++ b/relayer/pkg/chainlink/ocr2/client.go
@@ -173,10 +173,17 @@ func (c *Client) LinkAvailableForPayment(ctx context.Context, address *felt.Felt
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to call the contract with selector 'link_available_for_payment'")
 	}
-	if len(results) != 1 {
+	if len(results) != 2 {
 		return nil, errors.Wrap(err, "insufficient data from selector 'link_available_for_payment'")
 	}
-	return results[0].BigInt(big.NewInt(0)), nil
+
+	isNegative := !results[0].IsZero()
+	ans := results[1].BigInt(big.NewInt(0))
+	if isNegative {
+		ans.Neg(ans)
+	}
+
+	return ans, nil
 }
 
 func (c *Client) fetchEventsFromBlock(ctx context.Context, address *felt.Felt, eventType string, blockNum uint64) (eventsAsFeltArrs [][]*felt.Felt, err error) {